An object of the present invention is to provide an image processing apparatus that quickly and precisely measures or evaluates a distortion in a field of view and a charged particle beam apparatus. To attain the object, an image processing apparatus or the like is proposed which acquires a first image of a first area of an imaging target and a second image of a second area that is located at a different position than the first area and partially overlaps with the first area and determines the distance between a measurement point in the second image and a second part of the second image that corresponds to a particular area for a plurality of sites in the overlapping area of the first image and the second image.