A pattern inspecting method, comprising preparing a sample having a first and a second inspection regions and an imaging device having a plurality of pixels, scanning the first inspection region to a first direction using the imaging device to obtain a first measurement pattern representing at least parts of the first inspection region, scanning the second inspection region to the first direction using the imaging device to obtain a second measurement pattern representing at least parts of the second inspection region, comparing the first measurement pattern and the second measurement pattern with each other to determine presence or absence of a defect formed on the sample, and controlling a scanning condition for scanning a pattern of the second inspection region by the imaging device so as to keep the same with the scanning condition when the pattern of the first inspection region is scanned by the imaging device.