An occlusion correction improvement instrument includes an upper mold-mounting member provided with a plate-shaped member that is parallel to a Camper's plane of an upper model having a tooth model-shaped surface of a maxillary tooth row and with a plane parallel to the Camper's plane when the upper mold-mounting member has been mounted on the upper model; and a lower mold-mounting member mountable on a lower model having a tooth model-shaped surface of a mandible tooth row and provided with a pin-shaped projection portion that can be fixed, with a position thereof adjusted from side to side and up and down, and with an adjustment member that can adjust a position of the lower mold-mounting member relative to the upper mold-mounting member on the plane parallel to the Camper's plane, with the projection portion abut on the plate-shaped member of the upper mold-mounting member.