The present invention is an electronic device unit including an electronic device that has air inlets formed on a bottom surface of a main housing body having electronic components housed therein, and that introduces air to an inner part of the main housing body through the air inlets to cool the inner part of the main housing body, and a battery pack that is attached to the main housing body in a state where a battery case covers a part of a portion being an extensional region of the air inlets, wherein a surrounding wall part is provided on the bottom surface of the main housing body to surround a ventilation region in which the air inlets are provided and to be open at a portion facing the ventilation region, and the battery case is attached to the main housing body via protruding ends of the surrounding wall part.