A base section supports a revolution section. The revolution section supports a tilting section. The tilting section supports a seat section. The seat section includes a seat, a seat back and a step. The seat back has a restraining section. The restraining section includes an occipital region retainer and a temple retainer. Subject is seated with its occipital region and temples restrained by the restraining section. The head of subject is tilted on one side down from a head's horizontal plane in the Reid stereotaxic coordinate system to place one of left and right othlith organs within the head's horizontal plane. In this tilted position, different liner acceleration stimuli are applied to left and right otolith organs, respectively, for independent function tests of the left and right otolith organs.