An electrode forming region for providing lead electrodes (65a, 65b) is provided on a crystal resonator plate (2). Opposed side surfaces (67a, 67b) of a substrate (6) are formed and inclined in the same direction with respect to a front major surface (63). Also, an adhesion reinforcing portion (7) for reinforcing adhesion to a conductive adhesive (5) is provided in the electrode forming region for the lead electrodes (65a, 65b). For example, the adhesion reinforcing portion (7) is a notch portion which is cut and formed in the opposed side surfaces (67a, 67b). Thereby, an adhesion strength of the crystal resonator plate (2) and the conductive adhesive (5) is increased.