A radiation control method includes: calculating degrees of similarity corresponding to matching target areas; calculating a specific image position where a specific image area corresponding to a maximum value of the degrees of similarity out of the matching target areas is positioned in a radiographic image; and calculating a drive amount with which a therapeutic radiation ray irradiation device is driven, based on the specific image position. Further, calculating one degree of similarity corresponding to one matching target region out of the degrees of similarity includes: referring to a template table in which the matching target areas are associated with sets of templates to calculate a set of templates corresponding to the one matching target area out of the sets of templates; and detecting, from the set of templates, a similar template most similar to a matching target image displayed in the one matching target area of the radiographic image.