Variation in hole diameter due to heating effects is minimized even if the shortest machining route is set, and machining quality is improved. A printed circuit board to be scanned by a laser beam is divided into a plurality of scan areas (S1). An order of drilling within the scan area is sorted to obtain a scanning route with the shortest distance (S2). The order of the (N+1)th hole and the (N+2)th hole is swapped in each scanning area if it is determined that the distance between the Nth hole and the (N+1)th hole (here, N is an integer in a range of 1≦N≦“the maximum number of holes to be drilled in the area”−1″) is less than a predetermined threshold value, and that N+1 is not correspond to the maximum number of holes to be drilled in the scanning area (S3). The scanning area is machined and then machining each scanning area, specifically in machining the (N+1)th hole, after pausing for a period of a predetermined heat dissipation time if it is determined that the distance between the N-th hole and the (N+1)th hole swapped is less than the predetermined threshold value. Subsequently, machining is performed (S4).