PURPOSE: To prevent the deformation of a spoke core when synthetic resin is molded by interposing a core deformation preventing member in the gap between the core of a ring and a mold cavity radially disposed oppositely to the connecting portion of the core.

CONSTITUTION: A core deformation preventing member 5a is formed of a base 51 for engaging the outer periphery of a ring core 10 of a steering wheel and a projection 52 having the end surface 521 of the curvature coincident to the curvature of the surface of a mold cavity 7. The member 5a is engaged with the outer diameter side A of the core 10 of the side radially disposed oppositely to the connecting portion of a spoke core 30. The end surface 521 of the projection 52 of the member 5a is contacted with the surface of the cavity 7, thereby restricting the radial deformation of the core 10. When synthetic resin is injection- molded in this state, the core 10 is held at the center of the cavity 7 without deformation, thereby forming a steering wheel.