US Patent 7674188 Golf club head

A golf club head of this invention includes a face, a plurality of score line grooves formed on the face, and traces formed in the face by milling. Edges of the score line grooves are rounded with a radius of not more than 0.2 mm. A width W (mm) of the score line groove measured with the rounded edge being included, a width Ws (mm) between the score line grooves adjacent to one another, a width Wr (mm) of the score line groove measured based on the 30 degrees measurement rule and a cross section area S (mm2) of the score line grooves satisfy the flowing expressions; W/Ws×100≧35(%) and S/(Wr×0.5)×100≧70(%). The face in which the traces are formed has the arithmetic mean deviation of the profile (Ra) of not less than 4.00 μm.