Disclosed is a charged particle beam microscope which can obtain information about pattern materials and stereostructure without lowering throughput of pattern dimension measurement. To achieve this, the charged particle beam microscope acquires a plurality of frame images by scanning the field of view of the sample (S304, 305), adds the images together (S307), computes the dimensions of the pattern formed on the sample (308) and at the same time acquires pattern information (314) using components of a frame image, such as a single frame image or subframe image, as a separated image (309, 310).