When a communication port is occupied by a recording control unit, the communication port can be released as needed without causing an error or problem. A communication control unit 16 has a decision unit 44 that determines whether or not the USB port 18 can be released from the recording control unit 42 based on control commands input from the recording control unit 42 when the USB port 18 is occupied by the recording control unit 42 and an access request for the USB port 18 is received from another device, and a releasing unit 45 that releases the USB port 18 from the recording control unit 42 when the decision unit 44 determines that the USB port 18 can be released from the recording control unit 42.