A steering angle is corrected with reduced complicatedness in handling. Provided is a steering angle correction method, including: acquiring a measurement image of a steered wheel (14) in correspondence with a steering angle of a mobile object (10) at which the measurement image is captured; calculating a degree of coincidence between the steered wheel (14) on the measurement image and the steered wheel (14) on a reference image of the steered wheel (14) captured at a reference steering angle; and calculating a correction value used to correct the steering angle, based on the degree of coincidence.