An image forming device includes a plurality of image bearing members, a plurality of developing units, a plurality of toner cartridges, a plurality of shutter driving members, a driving force generating member that generates a driving force, and a driving force transmitting mechanism that transmits the driving force to the shutter driving members. Each toner cartridge includes a casing formed with an opening through which toner accommodated in the casing is supplied to the corresponding developing unit and a shutter movable between an opening position at which the shutter opens the opening and a closing position at which the shutter closes the opening. Each of the shutter driving members moves the corresponding shutter between the opening position and the closing position when supplied with the driving force.