An image forming apparatus including a sheet container, a sheet stacking member to closably open the sheet container; a restriction unit to restrict a swinging movement of the sheet stacking member, and a stopper mechanism to restrict insertion of the sheet container into the image forming apparatus in a state in which the sheet stacking member swings open from the sheet container. The stopper mechanism includes a stopped member provided to the sheet container and being movable vertically along the swinging movement of the sheet stacking member, and a stopper member provided to the image forming apparatus and being contactable with the stopped member. The stopped member includes a stopped surface contacted by the stopper member in a state in which the stopped member is lifted; and a switching surface adjacent to the stopped surface and vertically moving the stopped member by contact against the stopper member.