An object of the present disclosure is to provide a charged particle beam system capable of obtaining information about a sample by using a feature amount on an observed image caused by light interference, light diffraction, light standing waves, and the like caused by irradiating a sample with light, and the like. In the charged particle beam system according to the present disclosure, a first feature amount resulting from the light interference, the light diffraction, or the light standing wave generated by irradiating the sample with light is extracted from the observed image of the sample, and a second feature amount of the sample is obtained by using the first feature amount (see FIG. 6).