To provide an area extracting method which can automatically extract a specific area from a measurement area.

This is a method for extracting an extracted area 2 from a measurement area 1 including the extracted area 2 having a known detection pattern; and an extracting process for the entire measurement area 1 is performed by measurement ranges 4 and the position of the extracted area 2, about the measurement area 1 is specified according to the position of the measurement range 4 about the measurement area 1 or the position of the extracted area 2 in the measurement range. A reference pattern which is at least similar to the detection pattern is prepared and the measurement range which is larger than the extracted area is set in the measurement area to make a scan by specific movement quantities. The position of the measurement range about the measurement area is found from a scanning quantity. Each time a measurement range is scanned, a detection pattern matching the reference pattern is detected in the measurement range to find the position of the extracted area. The position of the extracted area about the measurement area is found from the position of the measurement range about the measurement area and/or the position of the extracted area about the measurement range.