1. A defect inspection apparatus comprising: a charged particle beam source which emits a charged particle beam to illuminate the charged particle beam onto a sample as a primary beam, the sample generating a secondary charged particle, a reflective charged particle, and/or a back-scattered charged particle from the surface thereof by the illumination of the primary beam; an image pickup which includes an imaging element having a light receiving face receiving at least one of the secondary charged particle, the reflective charged particle, and the back-scattered charged particle generated from the sample and which outputs a signal indicating a state of the surface of the sample; a mapping projection system which maps/projects at least one of the secondary charged particle, the reflective charged particle, and the back-scattered charged particle as a secondary beam and which makes the beam to form an image on the light receiving face of the imaging element; a controller which adjusts a beam diameter of the primary beam in such a manner as to apply the beam to the sample with a size smaller than that of an imaging region as a target of review to scan the imaging region and which allows the image pickup to pick up a plurality of frame images; an image processor which processes the plurality of obtained frame images to prepare a review image; and a defect judgment unit which judges a defect of the sample based on the review image.