Disclosed is an attached body detachably attached to a mobile communication terminal main body. The attached body includes a storage unit for storing an attached body identification number, content data, and access information showing an access destination of auxiliary information to utilize said content data in the mobile communication terminal. The attached body further includes a communication unit for transmitting the attached body identification number, the access information and the content data to the mobile communication terminal main body in accordance with demands from the mobile communication terminal main body.