PURPOSE: To provide an ion beam processing device capable of irradiating respective samples with ion beams with a simple structure.

CONSTITUTION: An ion beam generator 1, plural holding mechanisms 11 which attachably and detachably holds the respective plural samples to be irradiated with the ion beams, a treating chamber 4 in which processing by the ion beams is executed, a prepn. chamber 5 in which the samples are once stored, a transporting device 6 which transports the samples and plural holding mechanisms 11 are respectively subjected to first rotational driving to rotate the holding mechanisms 11 in such a manner that the samples rotate in the holding positions where the samples are held. Simultaneously, the device is provided with a rotational driving mechanism 3 which executes second rotational driving to rotate the holding mechanisms 11 so as to move the revolving axis of rotation moves on the predetermined circumference and a fine adjusting mechanism 23 which rotates the holding mechanisms 11 in such a manner that the samples rotate in the holding positions described above at the time when the rotational driving mechanism 3 does not execute the first rotational driving and the second rotational driving.