A device for detecting a riding posture is suitable for detecting a riding posture of a rider riding a bike. The device for detecting a riding posture includes a sensor and a controller. The sensor is connected to the bike to sense a relationship between the rider and the bike and output a sensing signal accordingly. The controller receives the sensing signal and determines the riding posture of the rider is a sitting posture or a standing posture according to the sensing signal.一種騎乘姿勢偵測裝置適於偵測正在騎乘一自行車的一騎乘者的騎乘姿勢。騎乘姿勢偵測裝置包括一感測器及一控制器。感測器連接至自行車，用以感測騎乘者與自行車之間的相互關係，並輸出對應的感測訊號。控制器接收感測訊號，並依照感測訊號判斷騎乘者的騎乘姿勢為坐姿或站姿。
