PURPOSE: To reduce the frequency fluctuation before and after sealing a case to a base executed by resistance welding, etc., by connecting a circuit element, a pair of plate spring-like holding tools and a prescribed number of terminals by a circuit, and thereafter, providing that which is molded integrally by resin molding on the base.

CONSTITUTION: A circuit element 5, a pair of plate spring-like holding tools 11 and a terminal 8 are connected by a circuit, and thereafter, molded integrally through a resin molding material 19. In such a way, even in the case a distortion is generated in a base due to resistance welding, etc., the distortion is not transmitted to a vibrator piece due to a fact that the plate spring-like holding tools 11 whose spring constant is small are deformed, the frequency fluctuation is reduced before and after resistance welding, and also, since the terminal 8 and the holding tools 11 can be positioned in advance, the molding work is facilitated and the workability is improved.