A golf club head is formed by integrally welding a face portion and a back portion
with each other. The face portion has a circumferential edge portion in its back
surface. The circumferential edge portion is made of a flat surface all over its
circumference. In the rear surface of the face portion, the part other than the
circumferential edge portion is formed as a recess portion. In the bottom surface
of the recess portion, a first bottom surface which is the deepest, a second bottom
surface which is the second deepest, a third bottom surface which is the third
deepest, and a fourth bottom surface which is the shallowest are formed in descending
order. Three ribs are provided vertically to extend through the recess portion.