diff --git a/web/src/components/EditableTimestamp.tsx b/web/src/components/EditableTimestamp.tsx
deleted file mode 100644
index 73b840247..000000000
--- a/web/src/components/EditableTimestamp.tsx
+++ /dev/null
@@ -1,104 +0,0 @@
-import { Timestamp, timestampDate } from "@bufbuild/protobuf/wkt";
-import { PencilIcon } from "lucide-react";
-import { useEffect, useRef, useState } from "react";
-import toast from "react-hot-toast";
-import { cn } from "@/lib/utils";
-
-interface Props {
-  timestamp: Timestamp | undefined;
-  onChange: (date: Date) => void;
-  className?: string;
-}
-
-const EditableTimestamp = ({ timestamp, onChange, className }: Props) => {
-  const [isEditing, setIsEditing] = useState(false);
-  const [inputValue, setInputValue] = useState("");
-  const inputRef = useRef<HTMLInputElement>(null);
-
-  const date = timestamp ? timestampDate(timestamp) : new Date();
-  const displayValue = date.toLocaleString();
-
-  // Format date for datetime-local input (YYYY-MM-DDTHH:mm)
-  const formatForInput = (d: Date): string => {
-    const year = d.getFullYear();
-    const month = String(d.getMonth() + 1).padStart(2, "0");
-    const day = String(d.getDate()).padStart(2, "0");
-    const hours = String(d.getHours()).padStart(2, "0");
-    const minutes = String(d.getMinutes()).padStart(2, "0");
-    return `${year}-${month}-${day}T${hours}:${minutes}`;
-  };
-
-  useEffect(() => {
-    if (isEditing && inputRef.current) {
-      inputRef.current.focus();
-      inputRef.current.showPicker?.(); // Open datetime picker if available
-    }
-  }, [isEditing]);
-
-  const handleEdit = () => {
-    setInputValue(formatForInput(date));
-    setIsEditing(true);
-  };
-
-  const handleSave = () => {
-    if (!inputValue) {
-      setIsEditing(false);
-      return;
-    }
-
-    const newDate = new Date(inputValue);
-    if (isNaN(newDate.getTime())) {
-      toast.error("Invalid date format");
-      return;
-    }
-
-    onChange(newDate);
-    setIsEditing(false);
-  };
-
-  const handleCancel = () => {
-    setIsEditing(false);
-    setInputValue("");
-  };
-
-  const handleKeyDown = (e: React.KeyboardEvent<HTMLInputElement>) => {
-    if (e.key === "Enter") {
-      handleSave();
-    } else if (e.key === "Escape") {
-      handleCancel();
-    }
-  };
-
-  if (isEditing) {
-    return (
-      <input
-        ref={inputRef}
-        type="datetime-local"
-        value={inputValue}
-        onChange={(e) => setInputValue(e.target.value)}
-        onBlur={handleSave}
-        onKeyDown={handleKeyDown}
-        className={cn(
-          "w-full px-2 py-1.5 text-sm text-foreground bg-background rounded-md border border-border outline-none transition-all focus:border-ring focus:ring-1 focus:ring-ring/20",
-          className,
-        )}
-      />
-    );
-  }
-
-  return (
-    <button
-      type="button"
-      onClick={handleEdit}
-      className={cn(
-        "group w-full text-left px-2 py-1.5 text-sm text-foreground/80 rounded-md transition-all flex items-center justify-between hover:bg-accent/50 hover:text-foreground",
-        className,
-      )}
-    >
-      <span className="font-normal">{displayValue}</span>
-      <PencilIcon className="w-3.5 h-3.5 opacity-0 group-hover:opacity-40 transition-opacity shrink-0 text-muted-foreground" />
-    </button>
-  );
-};
-
-export default EditableTimestamp;
diff --git a/web/src/components/MemoDetailSidebar/MemoDetailSidebar.tsx b/web/src/components/MemoDetailSidebar/MemoDetailSidebar.tsx
index f9659969a..76b6ea1e3 100644
--- a/web/src/components/MemoDetailSidebar/MemoDetailSidebar.tsx
+++ b/web/src/components/MemoDetailSidebar/MemoDetailSidebar.tsx
@@ -1,10 +1,7 @@
 import { create } from "@bufbuild/protobuf";
-import { timestampFromDate } from "@bufbuild/protobuf/wkt";
+import { timestampDate } from "@bufbuild/protobuf/wkt";
 import { isEqual } from "lodash-es";
 import { CheckCircleIcon, Code2Icon, HashIcon, LinkIcon } from "lucide-react";
-import toast from "react-hot-toast";
-import EditableTimestamp from "@/components/EditableTimestamp";
-import { useUpdateMemo } from "@/hooks/useMemoQueries";
 import { cn } from "@/lib/utils";
 import { Memo, Memo_PropertySchema, MemoRelation_Type } from "@/types/proto/api/v1/memo_service_pb";
 import { useTranslate } from "@/utils/i18n";
@@ -18,29 +15,10 @@ interface Props {
 
 const MemoDetailSidebar = ({ memo, className, parentPage }: Props) => {
   const t = useTranslate();
-  const { mutate: updateMemo } = useUpdateMemo();
   const property = create(Memo_PropertySchema, memo.property || {});
   const hasSpecialProperty = property.hasLink || property.hasTaskList || property.hasCode;
   const hasReferenceRelations = memo.relations.some((r) => r.type === MemoRelation_Type.REFERENCE);
 
-  const handleUpdateTimestamp = (field: "createTime" | "updateTime", date: Date) => {
-    const currentTimestamp = memo[field];
-    const newTimestamp = timestampFromDate(date);
-    if (isEqual(currentTimestamp, newTimestamp)) {
-      return;
-    }
-    updateMemo(
-      {
-        update: { name: memo.name, [field]: newTimestamp },
-        updateMask: [field === "createTime" ? "create_time" : "update_time"],
-      },
-      {
-        onSuccess: () => toast.success("Updated successfully"),
-        onError: (error) => toast.error(error.message),
-      },
-    );
-  };
-
   return (
     <aside className={cn("relative w-full h-auto max-h-screen overflow-auto flex flex-col justify-start items-start", className)}>
       <div className="flex flex-col justify-start items-start w-full gap-4 h-auto shrink-0 flex-nowrap">
@@ -56,13 +34,13 @@ const MemoDetailSidebar = ({ memo, className, parentPage }: Props) => {
 
         <div className="w-full space-y-1">
           <p className="text-xs font-medium text-muted-foreground/60 uppercase tracking-wide px-1">{t("common.created-at")}</p>
-          <EditableTimestamp timestamp={memo.createTime} onChange={(date) => handleUpdateTimestamp("createTime", date)} />
+          <p className="text-sm text-muted-foreground px-1">{memo.createTime ? timestampDate(memo.createTime).toLocaleString() : "-"}</p>
         </div>
 
         {!isEqual(memo.createTime, memo.updateTime) && (
           <div className="w-full space-y-1">
             <p className="text-xs font-medium text-muted-foreground/60 uppercase tracking-wide px-1">{t("common.last-updated-at")}</p>
-            <EditableTimestamp timestamp={memo.updateTime} onChange={(date) => handleUpdateTimestamp("updateTime", date)} />
+            <p className="text-sm text-muted-foreground px-1">{memo.updateTime ? timestampDate(memo.updateTime).toLocaleString() : "-"}</p>
           </div>
         )}
 
diff --git a/web/src/components/MemoEditor/components/TimestampPopover.tsx b/web/src/components/MemoEditor/components/TimestampPopover.tsx
new file mode 100644
index 000000000..63e00b3ea
--- /dev/null
+++ b/web/src/components/MemoEditor/components/TimestampPopover.tsx
@@ -0,0 +1,89 @@
+import { type FC, useRef, useState } from "react";
+import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
+import { useTranslate } from "@/utils/i18n";
+import { useEditorContext } from "../state";
+
+const DATETIME_FORMAT = "YYYY-MM-DD HH:mm:ss";
+
+function formatDate(date: Date): string {
+  const pad = (n: number) => String(n).padStart(2, "0");
+  return `${date.getFullYear()}-${pad(date.getMonth() + 1)}-${pad(date.getDate())} ${pad(date.getHours())}:${pad(date.getMinutes())}:${pad(date.getSeconds())}`;
+}
+
+function parseDate(value: string): Date | undefined {
+  const match = value.match(/^(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2}):(\d{2})$/);
+  if (!match) return undefined;
+  const date = new Date(Number(match[1]), Number(match[2]) - 1, Number(match[3]), Number(match[4]), Number(match[5]), Number(match[6]));
+  return Number.isNaN(date.getTime()) ? undefined : date;
+}
+
+const TimestampInput: FC<{
+  label: string;
+  date: Date | undefined;
+  onChange: (date: Date) => void;
+}> = ({ label, date, onChange }) => {
+  const initialValue = useRef(date ? formatDate(date) : "");
+  const [value, setValue] = useState(initialValue.current);
+  const [invalid, setInvalid] = useState(false);
+
+  const handleBlur = () => {
+    const parsed = parseDate(value);
+    if (parsed) {
+      setInvalid(false);
+      onChange(parsed);
+    } else {
+      setInvalid(true);
+    }
+  };
+
+  return (
+    <div className="space-y-1">
+      <label className="text-xs font-medium text-muted-foreground">
+        {label}
+        {value !== initialValue.current && <span className="text-primary ml-0.5">*</span>}
+      </label>
+      <input
+        type="text"
+        className="block w-full rounded-md border border-border bg-background px-2 py-1 text-sm font-mono data-[invalid=true]:border-destructive"
+        data-invalid={invalid}
+        placeholder={DATETIME_FORMAT}
+        value={value}
+        onChange={(e) => setValue(e.target.value)}
+        onBlur={handleBlur}
+      />
+    </div>
+  );
+};
+
+export const TimestampPopover: FC = () => {
+  const t = useTranslate();
+  const { state, actions, dispatch } = useEditorContext();
+  const { createTime, updateTime } = state.timestamps;
+
+  if (!createTime) return null;
+
+  return (
+    <Popover>
+      <PopoverTrigger asChild>
+        <button
+          type="button"
+          className="w-full text-sm text-muted-foreground -mb-1 text-left hover:text-foreground transition-colors cursor-pointer"
+        >
+          {formatDate(createTime)}
+        </button>
+      </PopoverTrigger>
+      <PopoverContent align="start" className="w-auto p-2 pt-1 space-y-1">
+        <TimestampInput
+          label={t("common.created-at")}
+          date={createTime}
+          onChange={(d) => dispatch(actions.setTimestamps({ createTime: d }))}
+        />
+        <TimestampInput
+          label={t("common.last-updated-at")}
+          date={updateTime}
+          onChange={(d) => dispatch(actions.setTimestamps({ updateTime: d }))}
+        />
+      </PopoverContent>
+    </Popover>
+  );
+};
diff --git a/web/src/components/MemoEditor/components/index.ts b/web/src/components/MemoEditor/components/index.ts
index 4a4ec4896..8949fbdca 100644
--- a/web/src/components/MemoEditor/components/index.ts
+++ b/web/src/components/MemoEditor/components/index.ts
@@ -9,3 +9,4 @@ export { LinkMemoDialog } from "./LinkMemoDialog";
 export { LocationDialog } from "./LocationDialog";
 export { default as LocationDisplay } from "./LocationDisplay";
 export { default as RelationList } from "./RelationList";
+export { TimestampPopover } from "./TimestampPopover";
diff --git a/web/src/components/MemoEditor/index.tsx b/web/src/components/MemoEditor/index.tsx
index ec05a99d3..1c20055df 100644
--- a/web/src/components/MemoEditor/index.tsx
+++ b/web/src/components/MemoEditor/index.tsx
@@ -9,7 +9,7 @@ import { handleError } from "@/lib/error";
 import { cn } from "@/lib/utils";
 import { useTranslate } from "@/utils/i18n";
 import { convertVisibilityFromString } from "@/utils/memo";
-import { EditorContent, EditorMetadata, EditorToolbar, FocusModeExitButton, FocusModeOverlay } from "./components";
+import { EditorContent, EditorMetadata, EditorToolbar, FocusModeExitButton, FocusModeOverlay, TimestampPopover } from "./components";
 import { FOCUS_MODE_STYLES } from "./constants";
 import type { EditorRefActions } from "./Editor";
 import { useAutoSave, useFocusMode, useKeyboard, useMemoInit } from "./hooks";
@@ -141,6 +141,8 @@ const MemoEditorImpl: React.FC<MemoEditorProps> = ({
         {/* Exit button is absolutely positioned in top-right corner when active */}
         <FocusModeExitButton isActive={state.ui.isFocusMode} onToggle={handleToggleFocusMode} title={t("editor.exit-focus-mode")} />
 
+        {memoName && <TimestampPopover />}
+
         {/* Editor content grows to fill available space in focus mode */}
         <EditorContent ref={editorRef} placeholder={placeholder} autoFocus={autoFocus} />
 
diff --git a/web/src/components/MemoEditor/state/actions.ts b/web/src/components/MemoEditor/state/actions.ts
index ec46bd05a..0c990c3e0 100644
--- a/web/src/components/MemoEditor/state/actions.ts
+++ b/web/src/components/MemoEditor/state/actions.ts
@@ -72,6 +72,11 @@ export const editorActions = {
     payload: value,
   }),
 
+  setTimestamps: (timestamps: Partial<EditorState["timestamps"]>): EditorAction => ({
+    type: "SET_TIMESTAMPS",
+    payload: timestamps,
+  }),
+
   reset: (): EditorAction => ({
     type: "RESET",
   }),
diff --git a/web/src/components/MemoEditor/state/reducer.ts b/web/src/components/MemoEditor/state/reducer.ts
index cc935f2bf..df0a0d3c3 100644
--- a/web/src/components/MemoEditor/state/reducer.ts
+++ b/web/src/components/MemoEditor/state/reducer.ts
@@ -119,6 +119,15 @@ export function editorReducer(state: EditorState, action: EditorAction): EditorS
         },
       };
 
+    case "SET_TIMESTAMPS":
+      return {
+        ...state,
+        timestamps: {
+          ...state.timestamps,
+          ...action.payload,
+        },
+      };
+
     case "RESET":
       return {
         ...initialState,
diff --git a/web/src/components/MemoEditor/state/types.ts b/web/src/components/MemoEditor/state/types.ts
index 48289b210..07aa732e5 100644
--- a/web/src/components/MemoEditor/state/types.ts
+++ b/web/src/components/MemoEditor/state/types.ts
@@ -45,6 +45,7 @@ export type EditorAction =
   | { type: "SET_LOADING"; payload: { key: LoadingKey; value: boolean } }
   | { type: "SET_DRAGGING"; payload: boolean }
   | { type: "SET_COMPOSING"; payload: boolean }
+  | { type: "SET_TIMESTAMPS"; payload: Partial<EditorState["timestamps"]> }
   | { type: "RESET" };
 
 export const initialState: EditorState = {