A physiological signal sensing device comprises a casing, a four-electrode, an electrocardiogram information processing module, an integrated fat information processing module, a switching module and a processing module. The four electrodes are respectively disposed on the outer casing, and each of the electrodes has a sensing surface exposed on the surface of the outer casing. The electrocardiogram information processing module, the body fat information processing module, the switching module and the processing module respectively Provided in the accommodating space, the switching module is connected to the four electrodes, and is controlled by the processing module to be connected to the electrocardiogram information processing module or the body fat information processing module, so that the processing module can be Provide an ECG information or a single fat message.一種生理訊號感測裝置，包含一外殼、四電極、一心電圖資訊處理模組、一體脂肪資訊處理模組、一切換模組及一處理模組。該四電極分別設置於該外殼，每一該電極具有一顯露於該外殼表面的感測表面，該心電圖資訊處理模組、該體脂肪資訊處理模組、該切換模組及該處理模組分別設置於該容置空間內，該切換模組連接該四電極，且受該處理模組的控制而選擇與該心電圖資訊處理模組或該體脂肪資訊處理模組導通，令該處理模組得以提供一心電圖資訊或一體脂肪資訊。
