An image-forming device includes: a cartridge receiving portion; a drive engaging unit; and a coupling member. The cartridge receiving portion receives a process cartridge detachably mounted therein. The drive engaging unit can move between an engaged position, in which the drive engaging unit transfers a driving force to the process cartridge, and a disengaged position, in which the drive engaging unit fails to transfer a driving force to the process cartridge. The coupling member moves the drive engaging unit between the engaged position and the disengaged position in association with mounting and detaching of the process cartridge in the cartridge receiving portion.