PURPOSE: To achieve a hole checking method for a hole checker in which a check can be performed in a short time, it can be made in an inline operation, and the throughput can be greatly increased.

CONSTITUTION: In a hole checking method for a hole checker wherein the respective holes 11 are optically detected by the hole checker while a drilled board 10 is conveyed in one direction A, dummy holes 12 of respective sizes are previously made in a free area of the board in the processing order simultaneously with the drilling with the respective sizes when drilling the board, and a check for the drilling is performed by detecting the number of the holes 11 as well as the sequence and sizes of the dummy holes 12.