A scanning electron microscope includes: a liner tube which transmits an electron beam; a scintillator having a through-hole into which the liner tube is inserted; a light guide which guides light generated by the scintillator; a conductive layer provided on a sensitive surface of the scintillator; and a conductive member provided in the scintillator, wherein the shortest distance between the liner tube and the conductive member is shorter than the shortest distance between the liner tube and the conductive layer, a voltage for accelerating electrons is applied to the conductive layer, and the conductive layer and the conductive member have a same potential.