ADVANCE ANGLE CORRECTION METHOD, ADVANCE ANGLE SETTING DEVICE, MOTOR DEVICE, AND IN-VEHICLE DEVICE

An advance angle correction method of a motor device includes: acquiring first advance angle correction information indicating a correspondence relationship between an advance angle correction amount and a rotation speed difference of a rotor of the motor calculated in advance based on a rotation speed change rate; measuring the rotation speed difference of the rotor; calculating a first advance angle correction amount for each rotation direction of the rotor as a first forward rotation advance angle correction amount and a first reverse rotation advance angle correction amount so that a rotation speed difference of an output shaft becomes smaller based on the first advance angle correction information and the rotation speed difference of the rotor; and storing the calculated first forward rotation advance angle correction amount and the first reverse rotation advance angle correction amount as advance angle correction information for each motor device.