Operations when connected to a personal computer and when charging a battery in a camera are made simple and easy to understand, and also a camera operation mode can be automatically changed to a communication mode. A digital camera has on its bottom a camera connector having a USB terminal, a DC input terminal and so on, and a cradle to have the digital camera mounted thereon has a cradle connector to be connected to the camera connector in synchronization with an operation of mounting the camera provided. The cradle has a power supply switch, a USB jack, a DC jack and so on provided thereon, and they are connected to the cradle connector. If the power supply switch is turned on with the digital camera mounted on the cradle, the digital camera starts up in a USB mode.