PURPOSE: To always accurately irradiate a material to be melted with electron beam, by providing a magnetic field detecting element in the vicinity of the material to be melted in a material evaporating apparatus by electron beam and correcting the locus of electron beam by the output signal thereof.

CONSTITUTION: Electron beam 4 from an electron gun 3 is deflected by 180° by a main deflection magnetic field 5 and project the material to be evaporated in a crucible 1 to melt and evaporate the same while the evaporated material is deposited to the surface of an objective material by vapor deposition or ion plating. In this case, a magnetic field detecting element 6 is provided in the vicinity of the material 2 to be evaporated and the change in the intensity of the magnetic field in the vicinity of the material 2 to be evaporated is detected. The output thereof is inputted to a correction circuit 7 and a correcting signal corresponding to the value of the magnetic field is sent to an electron beam locus correcting magnetic field 8. The correction of the locus is performed by this magnetic field 8 so as to accurately project the surface of the material 2 to be evaporated with electron beam 4.