PROBLEM TO BE SOLVED: To provide a brushless motor in which current loss can be compensated by simple circuitry, even if one phase of a polyphase winding is damaged due to partial failure of an inverter, or one phase of a polyphase winding fails.SOLUTION: The brushless motor comprises a neutral line (8) connecting the neutral (6a) of a power supply and the neutral (2a) of a star-connection in the winding, failure detection means (9) for detecting failure of any phase of a multiple-phase winding, a faulty phase determination means for determining whether there is a failure or not for each phase from the failure detection information input from a processing unit when a failure is detected in any phase by the failure detection means, and a phase control means for changing the phase of each phase current so that the current vector of a composite current of the X-axis and Y-axis quadrature components of each phase current, for which a determined is made that there is no failure by the faulty phase determination means, has a substantially circular trajectory.