A semiconductor device inspection apparatus having a noise subtraction function includes an electron gun, a stage for holding a sample, a main detector for detecting a signal discharged from the sample, and at least one or more sub detector for detecting noise generated from the sample or apparatus so that there can be obtained an image in which the noise caused by discharge generated on the sample or in the apparatus is removed from the signal. The noise subtraction function subtracts the noise detected by the sub detector from the signal detected by the main detector to remove or reduce the noise from the signal.