A holder unit is movable between an accommodated position and a pulled out position. A plurality of toner cartridges is detachably attached to the holder unit. A shutter provided on each toner cartridge is movable between a block position where the shutter blocks an opening of a case and an open position where the shutter opens the opening. An operation member of each toner cartridge operates the shutter such that the shutter moves between a first position and a second position. The shutter is located at the open position when the operation member is located at the first position. The shutter is located at the block position when the operation member is located at the second position. An interference member is configured such that the operation members abut the interference member to be displaced from the second position to the first position when the holder unit is moved from the pulled out position to the accommodated position.