A respiration rate detection device including a light source, an optical sensing unit and a processing unit is provided. The light source is configured to provide light to illuminate a skin region. The optical sensing unit is configured to detect emergent light from the skin region and output an intensity variation signal. The processing unit is configured to convert the intensity variation signal to frequency domain data and calculate a respiration rate according to the frequency domain data using at least one respiration algorithm.一種呼吸率偵測裝置，包含一光源、一光感測單元及一處理單元。該光源用以提供光線照射一皮膚區域。該光感測單元用以偵測經過該皮膚區域之出射光並輸出一亮度變化信號。該處理單元用以將該亮度變化信號轉換為頻域資料並利用至少一呼吸演算法根據該頻域資料計算一呼吸率。
