Patent ID: 8212224

Claim:
A charged particle beam device comprising: a cathode provided with a charged particle beam source which emits a charged particle beam and an anode which applies an electric field to the emitted charged particle; and a charged particle beam deflector which deflects an orbit of the charged particle beam having passed the anode and a charged particle beam detector which detects the charged particle beam from a sample to which the charged particle is irradiated; a distance changing mechanism in which a distance between said cathode and said anode is changed corresponding to the charged particle amount emitted from said charged particle source; and a deflection amount control mechanism which detects a condition of said deflector under which the charged particle beam amount detected from said sample scanned by deflecting the charged particle beam in said changed distance becomes a desired size and controls deflection of said deflector at sample measurement on the basis of said condition, wherein: said distance changing mechanism is provided with an anode position changing mechanism which changes an anode position and has a storage portion which stores condition data of the charged particle beam deflector corresponding to the anode position, a read-out portion which calls up the stored data from said storage portion, and an output portion which outputs the called-up data to the charged particle beam deflector, and said deflection amount control mechanism detects said condition by changing an output of the electron beam deflector on the basis of said called-up data and stores said detected condition in the storage portion.