PURPOSE: To be able to shorten the required time for an inspection by providing an upper limit value in the number of patterns stored in one memory, using a plurality of memories when the number of patterns exceeds the upper limit value when storing them in the memory, and setting a tact time on the basis of the upper limit value.

CONSTITUTION: The disposing region of patterns 1 are divided in a matrix state, patterns from data base 6 for inspection are stored in a memory 7 at each division, and sequentially compared with the pattern to be inspected for the stored pattern by setting a tact time. In such a pattern inspection, the number of the patterns 1 disposed in each division is recorded in the base 6, and an upper limit value is set to the number of patterns stored in one memory 7. A plurality of memories 7 are used to store the patterns for divisions (ij)n+1 exceeding the upper limit value in the number of patterns indicated from he base 7. A tact time is set on the basis of the upper limit value, the corresponding number of tacts is set to the same number as that of the memories used to store the patterns of the divisions in each division.