A fine pattern, such as a semiconductor integrated circuit (LSI), a liquid crystal panel, and a photomask (reticle) for the semiconductor or the liquid crystal panel, which are fabricated based on data for fabricating the fine pattern such as design data is inspected by a pattern inspection apparatus. The pattern inspection apparatus for inspecting a pattern to-be-inspected uses an image of the pattern to-be-inspected and data for fabricating the pattern to-be-inspected. The pattern inspection apparatus includes a reference pattern generation device configured to generate a reference pattern represented by one or more lines from the data, an image generation device configured to generate the image of the pattern to-be-inspected, a detecting device configured to detect an edge of the image of the pattern to-be-inspected, and an inspection device configured to inspect the pattern to-be-inspected by comparing the edge of the image of the pattern to-be-inspected with the one or more lines of the reference pattern.