In a terminal device, contents data from an attachment mounted on the device is received by a transmission/reception section and replayed by a first playback section. A detection section detects the mounting or removing of the attachment during the playback of the contents data. As an output destination for the contents data, a selection section selects the first playback section when the attachment has been mounted, or selects a first storage section when the attachment has been removed. In the attachment, the contents data is outputted to one of the first storage section and the first playback section based on the selection result of the terminal device. Accordingly, the usage mode of contents data can be readily changed with the mounting or removing of an attachment as a trigger.