According to one embodiment, a storage device includes a memory, a controller, an interface unit, a switch, and a switch control unit. The memory stores data. The controller is configured to control writing of data to the memory and reading of data from the memory. The interface unit includes a first terminal, a second terminal, and a third terminal. The first terminal has an electrical status different between a case where the storage device and a first device are connected, and a case where the storage device and a second device are connected. Through the second terminal, voltage is applied by the first device to the storage device in the case where the storage device and the first device are connected, and a control signal is input from the second device to the storage device in the case where the storage device and the second device are connected. Through the third terminal, power is supplied to the storage device. The switch switches a connection status and a disconnection status. In the connection status, the third terminal and the controller are electrically connected. In the disconnection status, the third terminal and the controller are electrically disconnected. The switch control unit is configured to control the switch to switch the connection status and the disconnection status based on electrical statuses of the first terminal and the second terminal.