PURPOSE: To enable a secure analysis of an insulator, by analyzing while attaching spattered atoms from a conductive solid near the sample, over the surface of the insulator sample.

CONSTITUTION: By deflecting scanning of ion beams, a conductive plate 3 is irradiated and spattered, and a conductive film of the spattered atoms is attached to the surface of an insulator sample 1. The conductive film makes a potential charged to the sample 1 escape through a secondary ion accelerating power source, so that electro static charge of the sample is prevented and a secure analysis can be performed.