An image forming apparatus includes an image bearing member; a developing device; and a movable member for rotationally moving the developing device. The movable member includes a rotation shaft member, a first member which is engaged with the rotation shaft member at one end portion, a second member which is engaged with the rotation shaft member at the other end portion, a first guide portion, and a second guide portion. The apparatus further includes a first swingable supporting member for rotatably supporting the movable member at the one end portion; a second swingable supporting member for rotatably supporting the movable member at the other end portion; an urging portion for urging the movable member toward the image bearing member; a first preventing member for preventing movement of the first member; and a second preventing member for preventing movement of the second member.