Patent ID: 8225662

Claim:
An acceleration sensing device, comprising: an outer frame; a first drive arm having both ends supported by sides of the outer frame through respective base parts, the sides opposing each other; a second drive arm extending from one of the base parts of at least one of the sides toward the other side; and a sensing arm that is disposed midway between the first drive arm and the second drive arm and extends from the one base part of the one side toward the other side, the sensing arm having an electrode in order to extract electric charge generated in the sensing arm, wherein: the first drive arm and the second drive arm have excitation electrodes for a flexural vibration and form a tuning fork type resonator; and center positions in thicknesses of sections that are located in the base parts and on an extension line of the first drive arm differ from a center position in a thickness of the first drive arm, the outer frame having a first narrowed section and a second narrowed section, the second narrowed section being disposed at a position remote from the first narrowed section with an opening of the outer frame interposed between the first and the second narrowed sections and in a direction orthogonal to an extended direction of the first drive arm.