Abstract: A DC commutatorless motor in which one pulse is generated per one revolution is disclosed. The motor comprises: three-phase stator windings; a rotor having 2n magnetic poles (where n is a natural number of 2 or more), a portion of one of the magnetic poles having a magnetic property different from that of said one magnetic pole; three detection devices disposed in the vicinity of said rotor, the detection devices being responsive to a magnetic field generated by the magnetic poles and the portion; first to third amplifiers for amplifying respectively the outputs of the three detection devices; first to third subtracting circuits for obtaining respectively the difference of the outputs of two of the first to third amplifiers; an adding circuit for adding the outputs of the first to third subtracting circuits; and a signal circuit for generating a pulse per one revolution of he rotor on the basis of the output of the adding circuit.