If a user is not familiar with the operation for a developer supply container, the rotating operation for the developer supply container may be insufficient, so that developer supply container does not reach a predetermined operating position, with the result of abnormal developer supply. By increasing a rotation load of a second gear which is in an operable connection with a drive gear member ofthe developer receiving apparatus by a function of a locking member, the developer supply container mounted to the developer receiving apparatus is rotated toward the supply position. After the developer supply container rotates to the supply position, the locking by the locking member is released, by which the rotation load applied to the second gear is reduced, so that drive transmission, thereafter, to the feeding member for developer supply is smooth.