A charged particle beam apparatus produces little reduction in resolution when the beam is inclined with respect to a sample. The trajectory of a primary beam 4 is deflected by a deflector or changed by a movable aperture such that the beam is incident on a plurality of lenses 6 and 7 off the axes thereof. A means is provided to control the off-axis trajectory of the beam such than an aberration produced by the objective lens 7 when the beam is inclined can be canceled by an aberration produced by the other lens 6.