diff --git a/packages/frontend/src/components/MkMediaVideo.vue b/packages/frontend/src/components/MkMediaVideo.vue
index d3a12ca734..4c2ff208dd 100644
--- a/packages/frontend/src/components/MkMediaVideo.vue
+++ b/packages/frontend/src/components/MkMediaVideo.vue
@@ -118,7 +118,7 @@ import { hms } from '@/filters/hms.js';
 import { defaultStore } from '@/store.js';
 import { i18n } from '@/i18n.js';
 import * as os from '@/os.js';
-import { isFullscreenNotSupported } from '@/scripts/device-kind.js';
+import { exitFullscreen, requestFullscreen } from '@/scripts/tms/fullscreen.js';
 import hasAudio from '@/scripts/media-has-audio.js';
 import MkMediaRange from '@/components/MkMediaRange.vue';
 import { $i, iAmModerator } from '@/account.js';
@@ -334,26 +334,21 @@ function togglePlayPause() {
 }
 
 function toggleFullscreen() {
-	if (isFullscreenNotSupported && videoEl.value) {
-		if (isFullscreen.value) {
-			// eslint-disable-next-line @typescript-eslint/ban-ts-comment
-			//@ts-ignore
-			videoEl.value.webkitExitFullscreen();
-			isFullscreen.value = false;
-		} else {
-			// eslint-disable-next-line @typescript-eslint/ban-ts-comment
-			//@ts-ignore
-			videoEl.value.webkitEnterFullscreen();
-			isFullscreen.value = true;
-		}
-	} else if (playerEl.value) {
-		if (isFullscreen.value) {
-			document.exitFullscreen();
-			isFullscreen.value = false;
-		} else {
-			playerEl.value.requestFullscreen({ navigationUI: 'hide' });
-			isFullscreen.value = true;
-		}
+	if (playerEl.value == null || videoEl.value == null) return;
+	if (isFullscreen.value) {
+		exitFullscreen({
+			videoEl: videoEl.value,
+		});
+		isFullscreen.value = false;
+	} else {
+		requestFullscreen({
+			videoEl: videoEl.value,
+			playerEl: playerEl.value,
+			options: {
+				navigationUI: 'hide',
+			},
+		});
+		isFullscreen.value = true;
 	}
 }
 
@@ -454,8 +449,10 @@ watch(loop, (to) => {
 });
 
 watch(hide, (to) => {
-	if (to && isFullscreen.value) {
-		document.exitFullscreen();
+	if (videoEl.value && to && isFullscreen.value) {
+		exitFullscreen({
+			videoEl: videoEl.value,
+		});
 		isFullscreen.value = false;
 	}
 });
diff --git a/packages/frontend/src/scripts/device-kind.ts b/packages/frontend/src/scripts/device-kind.ts
index 7c33f8ccee..095f55d9ce 100644
--- a/packages/frontend/src/scripts/device-kind.ts
+++ b/packages/frontend/src/scripts/device-kind.ts
@@ -11,13 +11,6 @@ const ua = navigator.userAgent.toLowerCase();
 const isTablet = /ipad/.test(ua) || (/mobile|iphone|android/.test(ua) && window.innerWidth > 700);
 const isSmartphone = !isTablet && /mobile|iphone|android/.test(ua);
 
-const isIPhone = /iphone|ipod/gi.test(ua) && navigator.maxTouchPoints > 1;
-// navigator.platform may be deprecated but this check is still required
-const isIPadOS = navigator.platform === 'MacIntel' && navigator.maxTouchPoints > 1;
-const isIos = /ipad|iphone|ipod/gi.test(ua) && navigator.maxTouchPoints > 1;
-
-export const isFullscreenNotSupported = isIPhone || isIos;
-
 export const deviceKind: 'smartphone' | 'tablet' | 'desktop' = defaultStore.state.overridedDeviceKind ? defaultStore.state.overridedDeviceKind
 	: isSmartphone ? 'smartphone'
 	: isTablet ? 'tablet'
diff --git a/packages/frontend/src/scripts/fullscreen.ts b/packages/frontend/src/scripts/fullscreen.ts
new file mode 100644
index 0000000000..7a0a018ef3
--- /dev/null
+++ b/packages/frontend/src/scripts/fullscreen.ts
@@ -0,0 +1,46 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+type PartiallyPartial<T, K extends keyof T> = Omit<T, K> & Partial<Pick<T, K>>;
+
+type VideoEl = PartiallyPartial<HTMLVideoElement, 'requestFullscreen'> & {
+	webkitEnterFullscreen?(): void;
+	webkitExitFullscreen?(): void;
+};
+
+type PlayerEl = PartiallyPartial<HTMLElement, 'requestFullscreen'>;
+
+type RequestFullscreenProps = {
+	readonly videoEl: VideoEl;
+	readonly playerEl: PlayerEl;
+	readonly options?: FullscreenOptions | null;
+};
+
+type ExitFullscreenProps = {
+	readonly videoEl: VideoEl;
+};
+
+export const requestFullscreen = ({ videoEl, playerEl, options }: RequestFullscreenProps) => {
+	if (playerEl.requestFullscreen != null) {
+		playerEl.requestFullscreen(options ?? undefined);
+		return;
+	}
+	if (videoEl.webkitEnterFullscreen != null) {
+		videoEl.webkitEnterFullscreen();
+		return;
+	}
+};
+
+export const exitFullscreen = ({ videoEl }: ExitFullscreenProps) => {
+	// eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+	if (document.exitFullscreen != null) {
+		document.exitFullscreen();
+		return;
+	}
+	if (videoEl.webkitExitFullscreen != null) {
+		videoEl.webkitExitFullscreen();
+		return;
+	}
+};