To provide a charged particle beam device that prevents variation of output peak values and has high SN ratio.

The charged particle beam device includes a determiner for determining whether an output signal is an output signal in the condition that one charged particle is incident to a detector or the output signal is an output signal in the condition that a plurality of charge particles are incident to the detector; and an operation unit for performing image formation with signal processing based on a pulse count method when determining that the output signal is an output signal in the condition that one charged particle is incident to the detector and performing the image formation with signal processing based on an analog method when determining that the output signal is an output signal in the condition that the plurality of charged particles are incident to the detector.

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