A mounting device for a support unit for commercial vehicles includes at least one supporting area, a first fixing area and a second fixing area, wherein the supporting area is configured to absorb the supporting forces in the supporting direction from the support unit or a support tube, wherein the first fixing area and the second fixing area are configured to fix the mounting device to a semi-trailer, wherein the first fixing area has at least one hole, wherein the second fixing area has at least one hole, and wherein the holes are configured to receive a fastener.