To form an anti-rolling device for making readily the adjustment- alteration of a parameter equivalent to a spring constant.

Moving slots are made at side surfaces of a gimbal for joining a gimbal 10 and gimbal rotating shaft 13, and they are fastened by fixing pieces 32 along the moving slot in use of fastening members 31 for fastening the gimbal 10 and gimbal rotating shaft 13. In this manner, a pendulum structure is formed by giving deflection between the center of gravity of the gimbal entirety and the gimbal rotating shaft so as to facilitate the adjustment-alteration of a parameter equivalent to a spring constant through the adjustment of position for fixing the gimbal rotating shaft 13.