PURPOSE: To manufacture various kinds of steering wheel in small quantity at low cost by a method wherein a core material covered with expandable soft vinyl chloride resin is expansion-molded by high-frequency heating in a simple mold made of material having a small power factor such as silicone resin or the like.

CONSTITUTION: A corel made of material with small power factor such as polypropylene or the like or of material with high thermal deformation temperature such as polycarbonate or the like is shaped into the form of steering wheel. A covered body 3 consisting in covering said core 1 with pieces 2 of expandable soft vinyl chloride resin having large power factor is arranged in simple forces 5 and 5', both of which are made of material with small power factor such as silicone resin or the like and pinched between electrodes 6 in order to expand the pieces 2 by applying high frequency voltage. Because the mold made of resin with small power factor is employed, only vinyl chloride resin can be efficiently expanded. In addition, because the mold itself is cheap, the provision of various kinds of mold is made possible, resulting in enabling to mold various kinds of steering wheel in small quantity at low cost.