To provide a digital storage device.

One multi memory card interface and one USB interface are collected into one common bus which is matched to a USB connector format, an associated switch circuit is provided, a circuit connection is constituted between the common bus and a flush memory, and a multi memory transfer function is provided. The digital storage device performs access of signals to the sole common bus, a USB transfer interface or an SD transfer interface which are connected via a connector board corresponding to the common bus and correspond to an electric device, an MMC transfer interface, an MSpro transfer interface, an XD transfer interface, an SM transfer interface, and a multi memory card transfer interface including a CF transfer interface.