Abstract: The present invention quickly calculates values of optimal excitation parameters which are set in lenses in multiple stages. A multi charged particle beam adjustment method includes forming a multi charged particle beam, calculating, for each of lenses in two or more stages disposed corresponding to object lenses in two or more stages, a first rate of change and a second rate of change in response to change in at least an excitation parameter, the first rate of change being a rate of change in a demagnification level of a beam image of the multi charged particle beam, the second rate of change being a rate of change in a rotation level of the beam image, and calculating a first amount of correction to the excitation parameter of each of the lenses based on an amount of correction to the demagnification level and the rotation level of the beam image, the first rate of change, and the second rate of change.