With the Z-axis given as a central axis, on an XY-plane, arranged are a rigid force receiving ring, a flexible detection ring inside thereof, and a cylindrical fixed assistant body further inside thereof. Two fixing points on the detection ring are fixed to a supporting substrate, and two exertion points are connected to the force receiving ring via connection members. When force and moment are exerted on the force receiving ring, with the supporting substrate fixed, the detection ring undergoes elastic deformation. Capacitance elements or others are used to measure distances between measurement points and the fixed assistant body and distances between the measurement points and the supporting substrate. Elastic deformation of the detection ring is recognized for mode and magnitude, thereby detecting a direction and magnitude of force or moment which is exerted.