Abstract: The rotation sensor (10) has a cylindrical first rotor (11) made of an insulating magnetic material, having conductor layers (11a) arranged circumferentially, the first rotor being attached to a rotating first shaft (5a) at a predetermined axial position; a fixed core (12) having an exciting coil (12b), the core being fixed to a fixing member with a space secured in the axial direction with respect to the first shaft; a second rotor (13) having nonmagnetic metal bodies (13b) arranged circumferentially to oppose the conductor layers respectively, the second rotor being attached to a second shaft located adjacent to and rotating relative to the first shaft (5a) and being located between the first rotor (11) and the fixed core (12); and oscillating device connected to the exciting coil (12b), the oscillating device transmitting an oscillation signal of a specific frequency.

Abstract: A rotation sensor (10) provided with a first rotor (11) fixed to a predetermined position in the axial direction of the shaft, a second rotor (12) fixed to the shaft (5) adjoining the first rotor, and a magnetic material core (13) having a resonance coil (13c) arranged around the first rotor and forming a magnetic circuit working with the first rotor. The first rotor (11) is formed by a magnetic material comprised of an insulator, an irregular magnetic field is formed with the magnetic material core, and the second rotor (12) is provided with a conductor cutting across areas of different intensities of the irregular magnetic field in accordance with the difference of the angle of rotation when a difference in the angle of relative rotation occurs at a shaft position where the first rotor is fixed and a shaft position where the second rotor is fixed.