An image forming apparatus includes a cartridge supporting member configured to move with respect to a main body of the apparatus in a state in which a cartridge is mounted to take a mounting and demounting position where the cartridge supporting member is located at an exterior of the main body and allowing the cartridge to be mounted and demounted, and an image forming position where the cartridge supporting member is located within an interior of the main body to locate the cartridge at a position which allows formation of an image. A first unit of the cartridge includes a position-restricted portion, and the cartridge is located below a second unit in which the cartridge is mounted on the cartridge supporting member. The cartridge supporting member includes a position restricting portion configured to restrict movement of the cartridge with respect to the cartridge supporting member by engaging the position-restricted portion.