To provide a storage apparatus to easily perform a data control such as printing and reading automatically or according to the instruction of a user in accordance with the purpose of a connected device.

This mass storage apparatus is provided with a switching means 3000 having a host function and a device function for switching the both functions. The mass storage apparatus is composed of: a device information management 3120 for managing the information of a connection device; an input/output device control means 3130 for controlling the connection device; and an input/output device control instructing means for instructing object data and a conversion format.