1. A defect analysis apparatus, comprising: a review-image acquisition unit for acquiring a review image of a partial region of a substrate on which patterns of a plurality of layers are formed; and a data processing unit for storing design data on configurations of said patterns formed in each layer of said substrate and judging criticality of a defect included in said review image of said partial region of said substrate acquired by said review-image acquisition unit; wherein said data processing unit; acquires, via said review-image acquisition unit, a review image of said partial region including said defect, compares said acquired review image with a predetermined reference image, and thereby extracts an image of said defect portion as a defect image from said review image, performs an alignment between a self-layer design pattern image and said review image by performing an image matching between said self-layer design pattern image and said review image, said self-layer design pattern image being generated from said design data, said design data belonging to a layer which is identical to said layer that includes said defect with respect to said partial region corresponding to said review image, generates data indicating a first relative position relationship between said defect and a pattern, said pattern belonging to a layer which is different from said layer that includes said defect, based on result of said alignment, said defect image, and an another-layer design pattern image being generated from design data belonging to a layer which is different from said layer that includes said defect with respect to said partial region corresponding to said review image, and judges said criticality, based on said generated data indicating said first relative position relationship, said criticality on which said defect affects said pattern belonging to said layer which is different from said layer that includes said defect.