Charged particle beam processing apparatus

A charged particle beam processing apparatus comprising:

• a sample chamber configured to process a substrate including a plurality of side faces by a charged particle beam;
• a movable stage provided in the sample chamber, the stage including a place on which the substrate is to be mounted;
• a height and position acquiring unit configured to acquire a height of the substrate on the stage by irradiating a laser beam onto the substrate mounted on the stage and using the laser beam reflected from the substrate and configured to acquire positions of at least two adjacent side faces among the plurality of side faces of the substrate mounted on the stage based on the acquired height of the substrate;
• and
• a calculating unit configured to calculate a position of center of gravity of the substrate mounted on the stage and a rotation angle as to a rotary axis vertical to the place on which the substrate is to be mounted based on the positions of the at least two adjacent side faces.