PURPOSE: To prevent an operation room body from largely vibrating in the case of swiveling operation, etc., and to make it possible to buffer vibration effectively.

CONSTITUTION: Rubber vibration insulators 25 forming buffer supports 23 on the left side are formed in the thick by specific size based on separation sizes from the swiveling centers O-O for rubber vibration insulators 24 of buffer supports 22 provided on the right side of an operation room body 8, and spring constant of each of the buffer supports 23 on the left side makes less than that of each of the buffer supports 22 on the right side. Even if a swiveling frame is largely flexed and vibrated, the buffer supports 23 on the left side absorb more vibration than the buffer supports 22 on the right side, and vibrations in all directions are quickly dumped.