Patent ID: 7112915

Claim:
A resonator piece, including: a base portion in which a base portion electrode portion is formed; resonating arm portions formed so as to project from the base portion; groove portions including groove electrode portions formed in front surfaces and/or back surfaces of the resonating arm portions; side surface electrode portions formed in side surfaces of the resonating arm portions in which the groove portions of the resonating arm portions are not formed; groove electrode-use connection electrode portions that connect the base portion electrode portion with the groove electrode portions; and side surface electrode-use connection electrode portions that connect the base portion electrode portion with the side surface electrode portions, a width of the base portion side of openings of the groove portions being formed narrower than a width of other portions, with connection electrode disposition portions for disposing the groove electrode-use connection electrode portions or the side surface electrode-use connection electrode portions being formed adjacent to the narrowly formed openings of the groove portions, and shapes of the openings of the groove portions being formed so as to be substantially symmetrical with respect to hypothetical lines disposed along a longitudinal direction at width-direction centers of the groove portions.