PURPOSE: To enable high speed annealing, and control of the region to be annealed, by preheating a sample by projection of low current electron beams on it, and then carrying out main heating through projection of high beam current.

CONSTITUTION: Information of the region to be annealed is fed to an irradiation position memory 5 through a computer 4 in advance. This computer 4 controls deflection of the electron beams, and movement of a stage 6 placing a wafer holder 2 and a wafer 3, and produces a signal so as to project constant current electron beams onto the prescribed position of the wafer 3 and to turn on and off the beams. Power supplies 9, 10 are changed over with a changeover switch 8. Low current electron beams are projected uniformly by excitement through turning on the supply 9 to preheat the wafer, and then main annealing is executed by turning on the supply 10 with the switch 8 and projecting high current beams.