The charged particle beam apparatus includes a charged particle beam optical system that irradiates a sample mounted on a sample stage with a charged particle beam; a detector that detects a signal generated from the sample; a charged particle beam imaging device that acquires an observation image from the signal detected by the detector; an optical imaging device that captures an optical image of the sample; a stage that rotatably holds the sample stage; a stage control device that controls movement and rotation of the stage; and an image composition unit that combines the plurality of optical images to generate a composite image. The stage control device is configured to move the stage so that the center of an imaging range of the optical imaging device is located at a position different from the rotation center of the stage and then, to rotate the stage, the optical imaging device acquires a plurality of optical images relating to different positions of the sample by rotation operation, and the image composition unit combines the plurality of optical images obtained by the rotation operation to generate a composite image.