The present invention provides a solid golf ball having long flight distance obtained by accomplishing high launch angle and low spin amount, and having excellent shot feel, rebound characteristics, scuff resistance and yellowing resistance. A regression test is performed using at least one pre-determined set of test data and one pre-recorded function test case corresponding to said signatures and being used to execute said at least one pre-recorded function test case. The main switch circuit having a first switch element that is a PMOS transistor and a second switch element that is an NMOS transistor connected to each other in parallel. Preferably the gearwheels and bearing axles are made of synthetic material.