Electron beam exposing apparatus

An electron beam exposing apparatus comprising:

• an electron gun having a cathode which is made of a single-crystal lanthanum hexaboride and which is shaped into a cone with half the vertical angle being between 60.degree. and 85.degree. such that the spread of the electron beam is kept below a predetermined value, that the luminous intensity of the electron beam is increased while still keeping said spread below said predetermined value and that the current density in a variably shaped aperture is kept uniform;
• means for heating said cathode at a given temperature to irradiate an electron beam of which a crossover image and an emission pattern are circular;
• means, including openings of variable shape, for shaping the electron beam irradiated from said cathode into the shapes of the openings;
• and
• means for focusing the shaped beam to form a beam spot having an area of 2 to 50 .mu.m.sup.2 on a sample.