There is provided an opening and closing apparatus, including: a main body; an openable body pivoting between a closed position and an open position; a connecting part connecting an end of the main body and an end of the openable body; a rack provided in one of the main body and the openable body; and an arm, wherein a part, of a pitch line of the rack, which makes contact with a pitch circle of the pinion in a state that the openable body is positioned in the vicinity of the closed position is an inclined line which is inclined to approach the other of the main body and the openable body having no rack, as the inclined line is farther away from the connecting part with the openable body being in the closed position.