Provided is a charged particle beam apparatus capable of analyzing foreign matters generated when a sample is transported or observed. The charged particle beam apparatus includes a sample stage on which a measurement sample is provided, a charged particle beam source that irradiates the measurement sample with a charged particle beam, and a detector that detects charged particles emitted by irradiation with the charged particle beam, and includes a foreign matter observation sample held on the sample stage together with the measurement sample and a foreign matter observation unit that causes a foreign matter to be observed on the foreign matter observation sample.