A loading device of chemical mechanical polishing (CMP) equipment for processing semiconductor wafers is provided. The loading device includes a loading cup having a cup-like bath, a cup plate installed in the bath, and a loading plate supported on the cup plate for absorbing shock and seating the wafer. A driving device and a driving shaft horizontally pivot and vertically move the loading cup between a platen of a polishing apparatus and a spindle. An arm connects the loading cup and the driving shaft. At least one through hole is located in a mutually corresponding position of the bath, the cup plate, and the loading plate of the loading cup. A probe assembly optically detects a polished thickness at a polished point on the wafer.