PURPOSE: To secure a super-precision multipole lens, by combining cylindrical and spherical lenses of various forms capable of obtaining the highest accuracy in a lens-making process.

CONSTITUTION: Electrodes 41W44 of given external form size, insulators 51W58, rods 59W62 having the same diameter with these insulators, screws 63W66 serving for both electrode fixation and voltage impressing and an outer cylinder for fixing insulator 67W70 and lens are made up in cylindrical or spherical form, while these insulators or non-magnetic materials are disposed so as to cause them to be inscribed in the inner circle of a tubular cylinder 71 without leaving the smallest clearance, and furthermore electrodes or magnetic poles are attached to two adjacent insulators or non-magnetic materials so that these electrodes or magnetic poles are set up with high accuracy. In this way, a super precision multipole lens can be secured.