An image forming device comprises a device main body; a cartridge attachable to the device main body; a main body transmission unit to rotate about a first rotation axis; a main body joint unit to rotate about a second rotation axis allowed to intersect with the first rotation axis; a cartridge transmission unit configured to rotate about a third rotation axis and to transmit a driving force to a rotation body; and a cartridge joint unit to rotate about a fourth rotation axis allowed to intersect with the third rotation axis. The cartridge joint unit is further configured to rotate coaxially with respect to the main body joint unit and to rotate the cartridge transmission unit when the main body transmission unit rotates in a state where the cartridge is attached to the device main body and the cartridge joint unit is coupled to the main body joint unit.