<p>A tire testing machine of the present invention includes a bottom chuck that is mounted to a bottom frame, a top chuck that is mounted to a movable beam, a ball screw that causes the movable beam to ascend or descend, and a beam fixing member that fixes the movable beam so as not to ascend. The beam fixing member includes a disk that is fixed to the ball screw and is provided with a plurality of elongated holes and air cylinders that are fixed to the vertical frame and are inserted into the elongated holes. When the pins are inserted into the elongated holes formed in the disk, the top chuck is fixed to the bottom chuck through the movable beam so as not to ascend.</p>
