To make information peripheral device to be easily carried and at the same time prevent its use form from being limited to a state that it is mounted in a slot of an information processor.

This information peripheral device is a card type peripheral device constituted of the shape (PCMCIA type) to be mounted in the slot provided in a PC(personal computer), is provided with an SD(secure digital) card slot in which an SD card can be mounted, a function to be operated as a conversion adaptor for the SD card mounted in the SD card slot when the information peripheral device is mounted in a slot of the PC, a communicating function to perform communication with the PC when it is not mounted in the slot of the PC, a peripheral device function to be operated as peripheral device of the PC by being connected by the communicating function and an independent device function to be operated as an independent device when it is not mounted in the slot and no communication is performed with the PC by the communicating function.