A method of reducing a registration error is provided in which the registration error can be uniformly distributed even if an amount of displacement is larger than others at only one of a plurality of measuring points. According to the method, amounts of displacement are measured first at a plurality of measuring points, then one half the sum of the maximum value and the minimum value of the measured amounts of displacement is calculated to obtain a correction value. The correction value is fed back to an exposure apparatus as a correction value for an exposure condition setting file within the exposure apparatus used in an exposure step. The registration error can be distributed uniformly even if amounts of displacement at a plurality of measuring points are considerably different from each other.