A developing apparatus comprising: a rotatable developer carrying member configured to carry developer; and a rotatable developer supply member in contact with the developer carrying member and configured to supply the developer to the developer carrying member, the developer supply member including a shaft extending in a rotational axis direction of the developer carrying member, a first driving member and a second driving member disposed at a first end portion of the shaft and a second end portion of the shaft opposite to the first end in the rotational axis direction, respectively, and a developer supply portion disposed between the first end portion of the shaft and the second end portion of the shaft in the rotational axis direction, wherein the first driving member is configured to receive a driving force for rotating the developer supply member, and the second driving member is configured to output the driving force to rotate the developer carrying member and has a hole, wherein the second driving member is mounted to the shaft without play in a rotational direction of the developer supply member with respect to the shaft by the shaft being press-fitted into the hole of the second driving member, wherein the hole of the second driving member includes an inner circumferential surface and a first flat surface, and the shaft includes an outer circumferential surface facing the inner circumferential surface and a second flat surface facing the first flat surface, and wherein a plurality of ribs (381a, 381b, 381c, 381d, 381e) are disposed on the inner circumferential surface and the first flat surface of the hole to provide an interference fit between the hole and the shaft. a rotatable developer carrying member configured to carry developer; and a rotatable developer supply member in contact with the developer carrying member and configured to supply the developer to the developer carrying member, the developer supply member including a shaft extending in a rotational axis direction of the developer carrying member, a first driving member and a second driving member disposed at a first end portion of the shaft and a second end portion of the shaft opposite to the first end in the rotational axis direction, respectively, and a developer supply portion disposed between the first end portion of the shaft and the second end portion of the shaft in the rotational axis direction, wherein the first driving member is configured to receive a driving force for rotating the developer supply member, and the second driving member is configured to output the driving force to rotate the developer carrying member and has a hole, wherein the second driving member is mounted to the shaft without play in a rotational direction of the developer supply member with respect to the shaft by the shaft being press-fitted into the hole of the second driving member, wherein the hole of the second driving member includes an inner circumferential surface and a first flat surface, and the shaft includes an outer circumferential surface facing the inner circumferential surface and a second flat surface facing the first flat surface, and wherein a plurality of ribs (381a, 381b, 381c, 381d, 381e) are disposed on the inner circumferential surface and the first flat surface of the hole to provide an interference fit between the hole and the shaft. wherein the hole of the second driving member includes an inner circumferential surface and a first flat surface, and the shaft includes an outer circumferential surface facing the inner circumferential surface and a second flat surface facing the first flat surface, and wherein a plurality of ribs (381a, 381b, 381c, 381d, 381e) are disposed on the inner circumferential surface and the first flat surface of the hole to provide an interference fit between the hole and the shaft.