A substrate loading device including a frame part forming a loading space in which a plurality of substrates are loaded, and having an inlet surface in which the substrates are inserted, and a rear surface opposite to the inlet surface, a main support protruding from the rear surface of the frame part to support a rear side of the loaded substrates and a sub support mounted at the inlet surface of the frame part and protruding from the inlet surface to support a front and opposite side of the loaded substrates.