Coupling structure between headrest stay and core member, headrest, and method for manufacturing the same

A method for manufacturing a headrest, the method comprising:

• a step of preparing a headrest stay having a pair of parallel right and left leg portions;
• a step of preparing a core member made of foam plastic provided with an elastic deformation piece configured to push an upper end portion of the headrest stay deep into a fitting groove having a substantially letter “U” shaped cross-section in an overhanging state with respect to an opening of the fitting groove, with the fitting groove in which the upper end portion of the headrest stay is inserted and fitted being formed in one surface of the core member;
• a step of coupling the headrest stay to the core member by inserting and fitting the upper end portion of the headrest stay in the fitting groove so as to spread out a distal end of each of the elastic deformation pieces;
• and
• a step of molding a cushion body in a skin by foaming a foam synthetic resin material in a filled state in the skin following coupling the headrest stay to the core member while holding the coupling structure portion in the skin,
• wherein the elastic deformation piece is integrally molded with the same material as the material of the core member.