An image forming apparatus includes a detachable-body mounted member, a detachable body and a sealing portion. The detachable-body mounted member includes a first opening and a first opening-and-closing member that opens and closes the first opening. The detachable body includes a second opening and a second opening-and-closing member. When the detachable body is attached, the second opening allows developer to flow into the first opening. The second opening-and-closing member opens and closes the second opening. When the detachable body is being attached or detached, the sealing portion seals a gap between (i) a front end face of the second opening forming member and (ii) a rear end face of the first opening-and-closing member.