A charged particle beam apparatus includes: an electromagnetic wave generation source 16 that generates an electromagnetic wave with which a sample is irradiated; a charged particle optical system that includes a pulsing mechanism 3 and irradiates the sample with a focused charged particle beam; a detector 10 that detects an emitted electron emitted by an interaction between the charged particle beam and the sample; a first irradiation control unit 15 that controls the electromagnetic wave generation source and irradiates the sample with a pulsed electromagnetic wave to generate an excited carrier; a second irradiation control unit 14 that controls the pulsing mechanism and irradiates an electromagnetic wave irradiation region of the sample with a pulsed charged particle beam; and a timing control unit 13. While the emitted electrons are detected by the detector in synchronization with irradiation of the pulsed charged particle beam, the timing control unit controls the first irradiation control unit and the second irradiation control unit, and controls an interval time between the pulsed electromagnetic wave and the pulsed charged particle beam to the electromagnetic wave irradiation region. As a result, based on a transient change in an electron emission amount, it is possible to detect sample information with nano spatial resolution.