A control device (50) for a charged particle beam device (100) tilts the irradiation axis of a primary electron beam (4) to the left, straight, or to the right via tilting coils (11, 12) each time the primary electron beam (4) scans the surface of a sample (15) over a single scanning line. When the irradiation axis is changed, the focal point of the primary electron beam (4) is adjusted by a focal point-adjusting coil (14) based on the tilt of the irradiation axis in order to take a left-tilted observation image, a non-tilted observation image or a right-tilted observation image of the surface of a sample (15) for each scanning line. The left-tilted observation images, non-tilted observation images and right-tilted observation images for the scanning lines obtained up to this point are simultaneously displayed on the same display device (31). In this way, focused non-tilted observation images and focused tilted observation images can be taken and displayed nearly simultaneously.