Abstract: A communication device includes: a first and a second connectors that are connectable to an external device via a first and a second cables, respectively; a detector that detects attachment and detachment of the second cable to the second connector; and a controller that communicates information on attachment and detachment of the second cable to the external device via the first cable, changes a communication mode from a first mode to a second mode when the second cable is attached to the second connector, and changes the communication mode from the second mode to the first mode when the second cable is detached from the second connector, the first mode being a mode in which the controller communicates with the external device via the first cable, and the second mode being a mode in which the controller communicates with the external device via the first and the second cables.