Disclosed is a cushioning material for a polishing pad, which hardly suffers swelling deformation caused by water because it is extremely low in water-absorbing characteristics and water-swelling characteristics. The cushioning material for a polishing pad includes a polyurethane foam capable of polishing even a semiconductor wafer having an undulated surface or a wafer having a local step that is formed during circuit forming process so that the undulation or step becomes smaller by uniformly polishing an entire surface of the wafer along the undulation or step. The cushioning material for a polishing pad is characterized by including a polyurethane foam obtained by reacting polyol and polyisocyanate with each other, the polyurethane foam having a contact angle with water of 90° or more. The polyurethane foam is preferably made by using hydrophobic polyol, and preferably has a self-skin layer formed thereon.