With a mounting operation of a supply container, a supported portion 11b of a developer receiving portion 11 is supported by a receipt supporting portion 30c of a lifting portion 30. With further mounting operation, a shutter sliding portion 30b of the lifting portion 30 slides on a shutter inclined portion 4f of a shutter 4. The developer receiving portion 11 is displaced so as to bring a receiving opening into communication with a discharge opening by operating, using the shutter 4, the lifting portion 30 supporting the supported portion 11b of the developer receiving portion 11. By this, a load required for movement of the developer receiving portion 11 is reduced to achieve smooth mounting of the supply container.