Seat cushion and method of manufacturing the same

A seat cushion is provided which can be easily recycled and has higher degree of freedom on the configuration and the construction. After a molded product composing the lower body 2 is placed in a mold, liquid polyurethane material is poured into the mold and is expanded to form the seat cushion 1. The molded product composing the lower body 2 is a polyurethane chip molded product, a polystyrene molded product, a polyethylene molded product, or a polypropylene molded product. The soft polyurethane foam composing the upper body has a 25 percent ILD hardness of 60 to 300N and a density of 20 to 80 kg/m.