With a multi-beam type charged particle beam apparatus, and a projection charged particle beam apparatus, in the case of off-axial aberration corrector, there is the need for preparing a multitude of multipoles, and power supply sources in numbers corresponding to the number of the multipoles need be prepared. In order to solve this problem as described, a charged particle beam apparatus is provided with at least one aberration corrector wherein the number of the multipoles required in the past is decreased by about a half by disposing an electrostatic mirror in an electron optical system.