An image forming apparatus includes: a main body provided with a drive-force supplying part; a cartridge comprising a rotary body and a drive-force transmission part; and a moving member supporting the cartridge. The drive-force transmission part transmits a drive force transmitted from the drive-force supplying part to the rotary body. The moving member is accommodated in and withdrawn from the main body. The cartridge is attached to and detached from the moving member when moving member is withdrawn from the main body. The moving member includes a drive-force relay part having an input portion and an output portion, the input portion receiving the drive force from the drive-force supplying part, the output portion outputting the drive force from the input portion to the drive-force transmission part of the cartridge attached to the moving member.