Electron beam direct printing apparatus

Printing pattern information from a printing pattern CAD is converted and output as deflection scanning data for the X-axis and the Y-axis by a deflection scanning data generating means. An electron beam deflection scanning means executes deflection scanning by an electron beam on a circuit printing base on the basis of the output deflection scanning data. The printing pattern irradiated with the electron beam is input to a bit map memory by dots which correspond to the points which are irradiated with the electron beam. A radiation control means can ascertain whether or not the point which is to be irradiated with the electron beam has already been subjected to beam irradiation at real time by consecutively reading out the dot information in the bit map memory at the address corresponding to the deflection scanning data. If there is no dot, a dot is written in the bit map memory simultaneously with beam irradiation, while if there is a dot, a blanking means outputs a control signal for cutting off the electron beam. Thus, overlap in printing pattern is detected at real time, thereby ensuring the avoidance of multiple beam radiation, namely, multiple exposure.