An image forming apparatus includes an apparatus body including positioning faces; a detachably attachable unit including receiving parts and contact parts; and a biasing member to press the receiving parts of the detachably attachable unit to the positioning faces disposed on the apparatus body. The biasing member is rotatably disposed to the apparatus body, contacts the contact parts disposed on the detachably attachable unit, presses the receiving parts against the positioning faces, and is elastically deformable in a direction separating from a rotary supporting point of the biasing member; and when the biasing member is rotated to a locked state from a release state, the biasing member is hooked to the contact parts, so that the receiving parts are pressed toward the positioning faces by the biasing member.