A defect observation method for observing a defect on a sample detected by another inspection device with a scanning electron microscope including the steps of: optically detecting the defect using the position information for the defect: illuminating the sample including the defect with an illumination intensity pattern having periodic intensity variation in two dimensions by irradiating a plurality of illumination light beams onto the surface of the sample while phase modulating the light beams in a single direction and successively moving the light beams in small movements in a direction different from the single direction, imaging the surface of the sample that is illuminated by the illumination intensity pattern having periodic intensity variation in two dimensions and includes the defect detected by the other inspection device, and detecting the defect detected by the other inspection device from the image obtained through the imaging of the surface of the sample.