The present invention is equipped with a USB interface 7 for being connected to a portable music player that is an external device, a browser button 27, a rotary encoder button 26, a back button 28, CPU 31 for acquiring a content list CL from the portable music player, RAM 33 for storing the content list CL acquired by the CPU 31, and a LED processing section 42 for changing how the rotary encoder button 26 illuminates to encourage the next operation at a time when the browse button 27 is operated. Accordingly, when searching pieces of music content stored in the portable music player that is an external device, one can unknowingly understand how to operate, thereby providing good operability even for searching pieces of music content of the external portable music player.