A developing apparatus, comprising: a frame configured to rotatably support a developing roller; a first end portion member provided at one end of the frame in an axial direction of the developing roller so as to be rotatable relative to the frame around a rotation axis parallel to the axial direction; and a second end portion member provided at another end of the frame in the axial direction so as to be rotatable relative to the frame around the rotation axis, wherein the first end portion member and the second end portion member can rotate independently of each other around the rotation axis, wherein the developing apparatus is configured to be removably mountable to an apparatus main body of an image forming apparatus in the axial direction, wherein at least one end portion member of the first end portion member and the second end portion member has a force receiving portion and a regulating portion, characterized in that the force receiving portion is provided on one side of said one end portion member in a first direction orthogonal to the rotation axis, and the force receiving portion is provided with a contact surface which is extending in a direction crossing a mounting direction of the developing apparatus and which is configured to receive biasing force from a biasing member of the apparatus main body by contacting with the biasing member in the mounting direction when the developing apparatus is mounted to the apparatus main body, the regulating portion is provided on the other side of said one end portion member in the first direction, and has a first abutting portion that is an inclined surface that is inclined to each of the rotation axis and the first direction and that is configured to be brought into abutment against the apparatus main body to regulate movement of the other side of said one end portion member relative to the apparatus main body in a direction opposite to the mounting direction, with a fulcrum being the rotation axis, and when the developing apparatus is positioned relative to the apparatus main body, the first abutting portion is brought into abutment against the apparatus main body in the direction while the force receiving portion is abutted by the apparatus main body in the mounting direction. a frame configured to rotatably support a developing roller; a first end portion member provided at one end of the frame in an axial direction of the developing roller so as to be rotatable relative to the frame around a rotation axis parallel to the axial direction; and a second end portion member provided at another end of the frame in the axial direction so as to be rotatable relative to the frame around the rotation axis, wherein the first end portion member and the second end portion member can rotate independently of each other around the rotation axis, wherein the developing apparatus is configured to be removably mountable to an apparatus main body of an image forming apparatus in the axial direction, wherein at least one end portion member of the first end portion member and the second end portion member has a force receiving portion and a regulating portion, the force receiving portion is provided on one side of said one end portion member in a first direction orthogonal to the rotation axis, and the force receiving portion is provided with a contact surface which is extending in a direction crossing a mounting direction of the developing apparatus and which is configured to receive biasing force from a biasing member of the apparatus main body by contacting with the biasing member in the mounting direction when the developing apparatus is mounted to the apparatus main body, the regulating portion is provided on the other side of said one end portion member in the first direction, and has a first abutting portion that is an inclined surface that is inclined to each of the rotation axis and the first direction and that is configured to be brought into abutment against the apparatus main body to regulate movement of the other side of said one end portion member relative to the apparatus main body in a direction opposite to the mounting direction, with a fulcrum being the rotation axis, and when the developing apparatus is positioned relative to the apparatus main body, the first abutting portion is brought into abutment against the apparatus main body in the direction while the force receiving portion is abutted by the apparatus main body in the mounting direction.