1. A pattern measurement device comprising: a storage section configured to store mask edge data of a circuit pattern of a semiconductor and image data obtained by imaging the circuit pattern; an SEM contour extracting section configured to receive the image data, extract a scanning electron microscope contour of the circuit pattern, and cause an exposure simulator to generate data of an estimated SEM contour on the basis of the mask edge data and data of the extracted SEM contour; a shape classifying section configured to receive the mask edge data, the SEM contour data, and the estimated SEM contour data to classify the SEM contour data and the estimated SEM contour data into a one-dimensionally shaped contour and a two-dimensionally shaped contour; and an SEM contour sampling section configured to receive the SEM contour data and the estimated SEM contour data to sample the SEM contour data on the basis of types of the one-dimensionally and two-dimensionally shaped contours.