diff --git a/Sora/CameraVideoCapturer.swift b/Sora/CameraVideoCapturer.swift
index cad7e266..3cec4064 100644
--- a/Sora/CameraVideoCapturer.swift
+++ b/Sora/CameraVideoCapturer.swift
@@ -54,26 +54,31 @@ public final class CameraVideoCapturer {
 
     /// 指定された設定に最も近い  AVCaptureDevice.Format? を返します。
     public static func format(width: Int32, height: Int32, for device: AVCaptureDevice, frameRate: Int? = nil) -> AVCaptureDevice.Format? {
-        let formats = RTCCameraVideoCapturer.supportedFormats(for: device)
-        var currentFormat: AVCaptureDevice.Format?
-        var currentDiff = INT_MAX
-        for format in formats {
+        func calcDiff(_ targetWidth: Int32, _ targetHeight: Int32, _ format: AVCaptureDevice.Format) -> Int32 {
             let dimension = CMVideoFormatDescriptionGetDimensions(format.formatDescription)
-            let diff = abs(width - dimension.width) + abs(height - dimension.height)
-            if diff < currentDiff {
-                currentFormat = format
-                currentDiff = diff
-            }
+            return abs(targetWidth - dimension.width) + abs(targetHeight - dimension.height)
+        }
 
-            // 解像度が一致し、フレームレートもサポートされている場合はその format を返す
-            let fpsRanges = format.videoSupportedFrameRateRanges
-            if frameRate != nil && width == dimension.width && height == dimension.height &&
-                fpsRanges.contains(where: { Int($0.minFrameRate) <= frameRate! && frameRate! <= Int($0.maxFrameRate) }) {
-                return format
-            }
+        let supportedFormats = RTCCameraVideoCapturer.supportedFormats(for: device)
 
+        // 指定された解像度に近いフォーマットを絞り込む
+        guard let diff = supportedFormats.map({ calcDiff(width, height, $0) }).min() else {
+            return nil
+        }
+        let formats = supportedFormats.filter { calcDiff(width, height, $0) == diff }
+        guard !formats.isEmpty else {
+            return nil
+        }
+
+        // この関数の引数に frameRate が指定された場合、フレームレートも考慮する
+        guard let frameRate else {
+            return formats.first
         }
-        return currentFormat
+        return formats.filter {
+            $0.videoSupportedFrameRateRanges.contains(where: {
+                Int($0.minFrameRate) <= frameRate && frameRate <= Int($0.maxFrameRate)
+            })
+        }.first ?? formats.first
     }
 
     /// 指定された FPS 値をサポートしているレンジが存在すれば、その値を返します。