In order to provide a method to easily and surely adjust the focal distance as in a Wobbler apparatus of the transmission type electron microscope method, a crossover 11 of a charged particle beam 2 is established between a charged particle gun 1 and an objective lens 6 and a beam deflection device 4 is provided to deflect the charged particle beam at the crossover point as the supporting point. One of these layers can be created as a coating using a conventional technique. A bridge extends from the proximal end of the first arm to the proximal end of the second arm.