An image forming apparatus includes an image carrier, an image forming member, a transferer, a toner image detector, and a controller. The transferer transfers the toner image from the image carrier directly or indirectly onto a recording medium transported by a surface moving member. The toner image detector detects a test toner image formed in a test toner image detection area located at an end portion of the surface moving member. The controller checks a length of the recording medium in a main scanning direction during continuous image formation, and forms the test toner image either in a space between recording media when the length of the recording medium exceeds a length of the surface moving member minus a length of the test toner image detection area in the main scanning direction or otherwise in parallel to the toner image transferred onto the recording medium.