A method and apparatus of detecting a defect by inspecting a specimen in which a surface of a specimen on which plural patterns are formed is illuminated with an elongated shape light flux from one of plural directions which are different in elevation angle by switching an optical path of the light flux emitted from an illuminating light source in accordance with a kind of defect to be detected. Plural optical images of the specimen illuminated by the elongated shape light flux are captured with plural image sensors installed in different elevation angle directions by changing an enlarging magnification in accordance with a density of the pattern formed on the sample in an area irradiated with the illuminating elongated shape light flux. A defect on the specimen is detected by processing the images captured by the plural image sensors.