In the present invention, at the time of measuring, using a CD-SEM, a length of a resist that shrinks when irradiated with an electron beam, in order to highly accurately estimate a shape and dimensions of the resist before shrink, a shrink database with respect to various patterns is previously prepared, said shrink database containing cross-sectional shape data obtained prior to electron beam irradiation, a cross-sectional shape data group and a CD-SEM image data group, which are obtained under various electron beam irradiation conditions, and models based on such data and data groups, and a CD-SEM image of a resist pattern to be measured is obtained (S102), then, the CD-SEM image and data in the shrink database are compared with each other (S103), and the shape and dimensions of the pattern before the shrink are estimated and outputted (S104).