Provided is a method for angle calibration of a rotary shaft, including: attaching a calibrating angular sensor to a first rotary shaft of an industrial machine including a plurality of rotary shafts and a control unit that controls the rotary shafts based on an angle detected by a controlling angular sensor provided for each rotary shaft, the calibrating angular sensor being more precise than the controlling angular sensor; connecting the calibrating angular sensor in place of the controlling angular sensor of a second rotary shaft; rotating the first rotary shaft; calculating a difference between a first angle of the first rotary shaft detected by the controlling angular sensor and a second angle of the first rotary shaft detected by the calibrating angular sensor; and storing the calculated difference as a calibration value for an angle of rotation of the first rotary shaft.