A scanning electron microscope which obtains a two-dimensional scan image of a sample includes an electron source and a scan deflector for scanning a primary electron ray generated from said electron source onto the sample. An objective lens forms a focusing magnetic field onto the sample, such as to surround the sample, the focusing magnetic field focusing the primary electron ray. A secondary signal detector for deflecting and detecting a secondary signal generated from the sample by irradiation of the primary electron ray obtains secondary electrons from a secondary electron conversion electrode for generating secondary electrons by collision of electrons, which is disposed between the objective lens and the detector at a location that is closer to the electron source than the objective lens is and at a location that is closer to the sample than the secondary signal detector is.