A method for manufacturing a golf club head includes providing a club head body produced by electric smelting an alloy base material including 0.04-0.07 wt % of carbon, 0.5-1.0 wt % of manganese, 0.5-1.0 wt % of silicon, less than 0.04 wt % of phosphorus, less than 0.03 wt % of sulfur, 15-17.7 wt % of chromium, 3.6-5.1 wt % of nickel, 2.8-3.5 wt % of copper, with the rest being iron and inevitable impurities. A solid solution treatment is proceeded at 1020-1080° C. for 80-100 minutes to form austenite and martensite in the club head body. A deep cooling treatment is proceeded between −120° C. and −80° C. for 7-9 hours to turn the austenite in the club head body into martensite. An aging treatment is proceeded on the club head body at 460-500° C. for 210-270 minutes to provide a hardness of HRC 36-46. A hosel is heated with high frequency waves at 900-1000° C. to posses a hardness lower than HRC 20.