An alignment correction method includes: the step of detecting coordinates of a first observation point 14 and a second observation point 15 set in advance on a substrate to be exposed 1 that is being scanned in a scanning direction A, in order to observe an alignment deviation of the substrate to be exposed 1; the step of computing a correction amount based on a deviation between the detected coordinates and a reference line set in advance according to the first observation point 14 and the second observation point 15; and the step of correcting alignment of a subsequent substrate to be exposed 1 based on the computed correction amount.