An image forming device comprising: a device main body; a cartridge detachably 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 configured to be able to rotate about a fourth rotation axis allowed to intersect with the third rotation axis, and 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.