A piezoelectric device, having a piezoelectric vibrating piece and a circuit element being electrically connected, is provided with a package for storing inside at least the piezoelectric vibrating piece of the piezoelectric device. The package is made up of a substrate and a cover body, and on the outer surface of the package, an electrode terminal electrically connected to at least the circuit element or the piezoelectric vibrating piece is provided. The electrode terminal includes an external connecting terminal which is electrically connected with an external circuit board and an input-output terminal which is electrically non-connected with the external circuit board, at the time of mounting the package on the external circuit board. The surface of the external connecting terminal and that of the input-output terminal are formed of materials different from each other so that adhesive characteristics to a mounting material such as a solder are varied. Thus, at the time of mounting the piezoelectric device on the external circuit board by using the mounting material such as the solder, short-circuit between the input-output terminal and the external connecting terminal is eliminated, and a highly reliable piezoelectric device is provided, having stable circuit operation without inducing characteristic deterioration.