This invention provides a plurality of grooves formed on a face of the golf club head. Each of a pair of side surfaces of each of the grooves has a first surface leading to the face and a second surface leading to the first surface in the depth direction of the groove. A first angle between the first surfaces of each of said pair of the side surfaces is larger than a second angle between the second surfaces of each of the said pair of the side surfaces. Edges of the groove are rounded. A width W (mm) of the groove measured including the rounded edges, a width Ws (mm) between the grooves adjacent one another, a width Wr (mm) of the groove measured based on the 30 degrees measurement rule and a cross section area S (mm2) of the groove satisfy the following expressions; W/Ws×100≧40(%), S/(Ws×0.5)×100≧70(%).