Golf ball 28 has a first side face 32, a second side face 34 and a third side face 36. The first side face 32 is positioned between an edge E and a point P. The second side face 34 is positioned between the point P and a point Q. The third side face 36 is positioned between the point Q and a point R. Each side face 32, 24, 36 is inclined in the in-depth direction toward the inward side. An angle .alpha.1 of the first side face 32 is 2.0.degree. or greater and 11.0.degree. or less. An angle .alpha.2 of the second side face 34 and an angle .alpha.3 of the third side face 36 are equal to or less than 30.0.degree.. The angle .alpha.3 is greater than the angle .alpha.2. The angle .alpha.2 is greater than the angle .alpha.1. The golf ball 28 also has a curved face 38. The curved face 38 is a part of a spherical surface.