EXTERNAL FORCE DETECTION SENSOR AND EXTERNAL FORCE DETECTION EQUIPMENT

An external force detection sensor includes a piezoelectric piece, excitation electrodes, an oscillation circuit, a movable electrode, and a fixed electrode. The fixed electrode forms variable capacitance with variation in capacitance between the fixed electrode and the movable electrode that is caused by deflection of the piezoelectric piece. The piezoelectric piece, the excitation electrode, the movable electrode, and the fixed electrode constitute combinations of a first combination and a second combination. The first combination constitutes a first sensor unit by disposing a first piezoelectric piece on a first crystal plane of the crystalline body. The second combination constitutes a second sensor unit by disposing a second piezoelectric piece on a second crystal plane. The second crystal plane does not opposite to the first crystal plane of the crystalline body. A relative position of the second crystal plane with respect to the first crystal plane is obtained.