To provide a shutter mechanism allowing an exposure time by a charged particle beam to be set short.

This shutter mechanism has: a first shutter plate 9a driven for blocking and releasing an electron beam (charged particle beam) 2; and a second shutter plate 9b having an opening part 9e formed for passing the charged particle beam and rotatable at a predetermined rotation period. When the shutter plate 9b is being rotated, the releasing time of the particle beam 2 by the shutter plate 9a is set in line with the rotation period of the shutter plate 9b. In this case, the opening time of the shutter plate 9a is set equal to the rotation period of the shutter plate 9b for instance.