FORCE SENSOR

A force sensor according to the present invention includes a closed loop shaped deformable body and a detection circuit that outputs an electric signal indicating an applied force or a moment on the basis of elastic deformation generated in the deformable body. The deformable body includes at least two fixed portions, at least two force receiving portions adjacent to the fixed portion in a closed loop shaped path of the deformable body, and a deformable portion positioned between the fixed portion and the force receiving portion adjacent to each other in the closed loop shaped path. The deformable portion includes: a main curved portion having a curved main curved surface; a fixed portion-side curved portion connecting the main curved portion to the corresponding fixed portion and having a fixed portion-side curved surface; and a force receiving portion-side curved portion connecting the main curved portion to the corresponding force receiving portion and having a force receiving portion-side curved surface. Both of the curved surfaces are provided on the positive side on the Z-axis or the negative side on the Z-axis of the deformable portion, with mutually different curved directions. The detection circuit outputs an electric signal on the basis of elastic deformation generated in the main curved portion.