PURPOSE: To form a cushion pad integrally with a surface material by foaming by finishing smoothly the peripheral portions of holes on a surface material from which head rest pillars protrude to prevent the resin foam from leaking outside the surface material so that the head rest can swing smoothly without generating noise.

CONSTITUTION: A stand-up portion 11a that allows the head rest body to swing in forward and backward directions of a seat is provided on the bottom of a head rest frame 11 from which head rest pillars 10a protrude, whereas a long hole 12a is sealed by forcibly sandwiching the peripheral portion of the holes on the surface material 12 with the front edge of the stand-up portion 11a and the inner face of a forming mold 20; a cushion pad 13 is formed by foaming integrally with the surface material 12; and the peripheral portions of the holes on the surface material 12 are put onto the front edge of the stand-up portion 11a to fix them thereon.