A developer supplying system comprising: a developer receiving apparatus including driving means for applying a driving force; and a developer supply container which is detachably mountable to the developer receiving apparatus and which is set by a setting operation including at least a rotation thereof from a position where mounting and dismounting thereof is permitted through a predetermined angle in a setting direction, said developer supply container comprising: a container body (1a; 800) for storing developer; rotatable developer discharging means for discharging the developer in said container body (1a; 800); and transmitting means (5, 6; 5, 16) for transmitting the driving force from the driving means to said developer discharging means, characterized in that said developer supply container comprises suppressing means movable between an operating position in which a relative rotation of said transmitting means (5, 6; 5, 16) relative to said developer supply container is suppressed to rotate said developer supply container in the setting direction by the driving force received from said driving means, and a non-operating position, said developer receiving apparatus includes moving force applying means (10j, 10k) for applying a force for moving the suppressing means of said developer supply container from the non-operating position toward the operating position, said suppressing means has moving force receiving means for receiving, from said moving force applying means (10j, 10k), a force for moving said suppressing means from the non-operating position toward the operating position, and when said developer supply container is made to rotate from the position where mounting and dismounting thereof is permitted through the predetermined angle in the setting direction, said transmitting means (5, 6; 5, 16) operatively engages with said driving means, and then said developer supply container rotates in the setting direction toward a supplying position by the driving force received by said transmitting means (5, 6; 5, 16). a developer receiving apparatus including driving means for applying a driving force; and a developer supply container which is detachably mountable to the developer receiving apparatus and which is set by a setting operation including at least a rotation thereof from a position where mounting and dismounting thereof is permitted through a predetermined angle in a setting direction, said developer supply container comprising: a container body (1a; 800) for storing developer; rotatable developer discharging means for discharging the developer in said container body (1a; 800); and transmitting means (5, 6; 5, 16) for transmitting the driving force from the driving means to said developer discharging means, a container body (1a; 800) for storing developer; rotatable developer discharging means for discharging the developer in said container body (1a; 800); and transmitting means (5, 6; 5, 16) for transmitting the driving force from the driving means to said developer discharging means, characterized in that said developer supply container comprises suppressing means movable between an operating position in which a relative rotation of said transmitting means (5, 6; 5, 16) relative to said developer supply container is suppressed to rotate said developer supply container in the setting direction by the driving force received from said driving means, and a non-operating position, said developer receiving apparatus includes moving force applying means (10j, 10k) for applying a force for moving the suppressing means of said developer supply container from the non-operating position toward the operating position, said suppressing means has moving force receiving means for receiving, from said moving force applying means (10j, 10k), a force for moving said suppressing means from the non-operating position toward the operating position, and when said developer supply container is made to rotate from the position where mounting and dismounting thereof is permitted through the predetermined angle in the setting direction, said transmitting means (5, 6; 5, 16) operatively engages with said driving means, and then said developer supply container rotates in the setting direction toward a supplying position by the driving force received by said transmitting means (5, 6; 5, 16).