A motor feeding a sheet of paper is arranged inside a frame, and below the motor, a motor cover having a detecting portion for detecting presence/absence of a cartridge is attached on a base member. A signal caught by the detecting portion is transmitted through a wire to a substrate portion arranged outside the frame. The base member has a first cut-and-raised portion formed for engaging with the motor cover, and a second cut-and-raised portion formed at a prescribed position. The wire is connected, through a gap formed by the first cut-and-raised portion between the motor cover and the base member and through the second cut-and-raised portion, to the substrate portion. Thus, a laser printer apparatus can be provided in which the wire connecting the detecting portion detecting presence/absence of a cartridge to the substrate portion can be routed to avoid any influence of heat, at a low cost.