Abstract: A method of molding a headrest of automotive seat comprises the following steps. First, a bag shaped flexible outer skin member is prepared, has an elongate slit formed therethrough. A part of a stay member is inserted into the outer skin member through the slit and set relative to the outer skin member. A given biasing force is applied to longitudinal ends of the slit so that the slit is stretched in longitudinally opposed directions and thus caused to take a closed position. Then, an injection nozzle of a foamable material feeder is put into the slit by expanding the slit against the biasing force. A foamable material is poured into the outer skin member, and the material feeding is stopped when a given amount of material is fed to the outer skin member. The application of the biasing force to the slit is continued until the material is sufficiently cured.