A charged particle beam device includes: a charged particle beam source; an analyzer that analyzes and detects particles including secondary electrons and backscattered charged particles that are emitted from a specimen by irradiating the specimen with a primary charged particle beam emitted from the charged particle beam source; a bias voltage applying unit that applies a bias voltage to the specimen; and an analysis unit that extracts a signal component of the secondary electrons based on a first spectrum obtained by detecting the particles with the analyzer in a state where a first bias voltage is applied to the specimen, and a second spectrum obtained by detecting the particles with the analyzer in a state where a second bias voltage different from the first bias voltage is applied to the specimen.