Abstract: This invention relates to a power source apparatus using piezoelectric elements. A conventional power source apparatus using the piezoelectric element has an ability of generating less electricity, and therefore, has been applicable only to equipment which operates with low power consumption. To solve the problems of the conventional power source apparatus, the inventor has devised a “power source apparatus” and disclosed in Japanese Utility Model Registration No. 3074105. However, the devised power generating device has the Zener diode used as the trigger circuit determining the quantity of the charged electricity. Therefore, it is necessary to operate the trigger circuit all the time, consequently to use too much electricity to operate. The electrical power consumption therefor is unignorable compared with the electric energy generated by the piezoelectric element.