A head 2 includes a face part 4. The face part 4 includes a plurality of constant thickness regions S1 and S2, and a plurality of thickness transition regions R1, R2 and R3. The constant thickness regions include a first constant region S1 and a second constant region S2 which is thinner than the first thickness region S1. The thickness transition regions R1, R2 and R3 which are adjacent to each other is disposed between the first constant region S1 and the second constant region S2. The thickness transition regions adjacent to each other have different thickness change rates from each other.