A method and apparatus for detecting defects includes irradiating and scanning an electron beam focused on an area of a sample, detecting charged particles generated from the sample by the irradiating and scanning of the electron beam with a first detector which detects charged particles having relatively low energy to obtain a first image of the area and with a second detector which detects charged particles having relatively high energy to obtain a second image of the area, comparing the first inspection image of the area with a first reference image to generate a first difference image, and comparing obtained second image of the area with a second reference image to generate a second difference image, and detecting an open defect or a short defect from at least one of the generated first difference image and the second difference image.