An iron club head includes a striking plate for striking a golf ball and a body. The body includes an elastically deformable thin wall. An opening is defined in a front side of the body and surrounded by the thin wall. The striking plate is bonded in the opening. The thin wall has a thickness smaller than that of the striking plate. When the iron club head hits a golf ball, a momentum of striking generated as a result of hitting the golf ball causes elastic deformation of the striking plate and the thin wall to increase an overall deformation of the iron club head.