According to one embodiment, a pattern inspection apparatus includes a first inspection data creation section, a first delay section, a first recognition section, a first extraction section, a first and a second level difference calculation section, a first and a second determination section, and a first logic OR calculation section. The first extraction section extracts data of a sub-resolution pattern from the first inspection data and the first delay data. The first and second level difference calculation section calculate differences between an average output level of a surrounding region for a target pixel of the extracted data from the first inspection data or the first delay data and an output level of the extracted data. The first and second determination sections determine presence or absence of a defect. The first logic OR calculation section calculates logic OR of determination results of the first and second determination sections.