It is an object of the present invention to obtain an ultrathin angle detector by disposing an annular rotor board face to face with stator windings of a plurality of stators provided on an annular stator board. An angle detector according to the present invention is constructed by providing magnetic cores and the stator windings on the respective stators provided on a surface of the annular stator board via slots, and disposing a corrugated curved surface formed on a board inner surface of the annular rotor board face to face with the stators so as to obtain an angular signal that changes according to a sinusoidal waveform.
