The present invention addresses the problem of providing a sample inspection device and a sample inspection method, whereby noise is removed from a detection signal, and a generated electron beam is utilized effectively for inspection. A sample inspection device according to the present invention is provided with a light source for emitting frequency-modulated light, a photocathode for emitting an electron beam in response to receiving the frequency-modulated light, a detector for detecting electrons emitted from a sample irradiated by the electron beam and generating a detection signal, and a signal extractor for extracting a signal having a frequency corresponding to a modulation frequency of the frequency-modulated light from within the detection signal.