Capacitive sensor, acoustic sensor and microphone

A capacitive sensor comprising:

• a substrate having a cavity that is open at least at an upper surface;
• a vibrating electrode plate formed above the substrate so as to cover an upper portion of the cavity;
• a plurality of anchors that are arranged with a gap in an outer peripheral portion of the vibrating electrode plate and enable the vibrating electrode plate to be fixed to a stationary member;
• and
• a fixed electrode plate arranged so as to oppose the vibrating electrode plate,
• wherein in a view from a direction perpendicular to an upper surface of the substrate, an entire length of an outer edge of the vibrating electrode plate located between adjacent anchors is located outward of a tangent that circumscribes edges of the adjacent anchors on a side distant from a center of the vibrating electrode plate, and
• one or two or more openings are provided in regions of the vibrating electrode plate that are in a vicinity of the anchors.