To effectively suppress a shift of a rotating axis of an upper chuck with respect to a rotating axis of a lower chuck due to a separating force. A tire testing device (1) includes: vertical frames (30a, 30b) which are supported by a lower frame (20); a beam (40) which bridges between the vertical frames (30a, 30b) and is movable in the vertical direction; an upper chuck (45) which is attached to the center of the beam (40), the center corresponding to the center of the beam in the longitudinal direction; and a lower chuck (25) which is attached to the lower frame. When viewed from the vertical direction, a rotating axis of an upper rotating member (47) is positioned at the center of a straight line formed by connecting supporting points where each of the vertical frames (30a, 30b) support the beam (40).