PURPOSE: To prevent occurrence of insufficient pattern matching by discarding any fraction less than the boundary value of edge data values by edge filtering.

CONSTITUTION: The title method uses an electron beam device. At the time of performing alignment between LSI design data and an SEM image, the alignment between the design drawing of a mask obtained from an LSI design data storing means 3 and the SEM image obtained from an SEM image storing means 2 is performed by using a wiring edge. The filtering 5 of the wiring edge is performed by providing a boundary value for separating the edge data row of the SEM image prepared at the time of pattern matching into effective data and noneffective data and setting a prescribed value to the noneffective data. Therefore, the S/N of the edge data row can be improved and the occurrence of insufficient pattern matching can be prevented.