A defect inspecting apparatus is provided for generating a less distorted test image to reliably observe a surface of a sample for detecting defects thereon. The defect detecting apparatus comprises a primary electron beam source for irradiating a sample, electrostatic lenses for focusing secondary electrons emitted from the surface of the sample irradiated with the primary electron beam, a detector for detecting the secondary electrons, and an image processing unit for processing a signal from the detector. Further, a second electron source may be provided for emitting an electron beam irradiated to the sample, wherein the sample may be irradiated with the electron beam from the second electron source before it is irradiated with the primary electron beam from the first electron source for observing the sample. A device manufacturing method is also provided for inspecting devices under processing with high throughput using the defect detecting apparatus.