A digital camera is composed of a camera body and a lens unit removebly attached to the camera body. When the lens unit is attached to the camera body, the lens unit and camera body send and receive control signals by antennas and wireless I/Fs each disposed on the lens unit and the camera body, respectively. In addition, data of the image captured with the lens unit is sent to the camera body by serial drivers, each disposed on the lens unit and the camera body, through connection contacts that electrically connect the lens unit and the camera body. When the lens unit is detached from the camera body, on the other hand, the control signals are sent and received by the antennas and the wireless I/Fs, and the image data is sent by the wireless communication.