A sensorless control method for a motor is provided to correctly detect a position of a magnetic pole of a permanent magnet synchronous motor without a sensor by calculating the position of the magnet pole of the motor based on the detected polarity of current and the detected current value. A sensorless control method for a motor includes the steps of: detecting a U-phase current which is applied from a first electric angle to a motor(S12); detecting a V-phase current which is applied from a second electric angle to the motor(S13); detecting a W-phase current which is applied from a third electric angle to the motor(S14); and calculating a position of the motor based on the detected polarity of each current and the detected current value(S15). The motor is a permanent magnet synchronous motor. The first electric angle is 0 degree. The second electric angle is 120 degrees. The third electric angle is 240 degrees.
