The invention relates to means for preventing bounce up of a table surface portion of a lying table with a hydraulic cylinder. In the invention, at a side part of the table surface portion which is apt to bounce up, a first engaging member is arranged on a hydraulic cylinder side support member (6h), and a second engaging member is arranged on a table surface portion side support member (9h) which is supported by the hydraulic cylinder side support member (6h). When the table surface portion (3) moves towards the above with respect to the hydraulic cylinder from a horizontal state, the first engaging member and the second engaging member engage and prevent relative rotation so as to be able to prevent the bounce up of the table surface portion. The first engaging member and the second engaging member can be configured by a shaft member (12) and a recessed portion (13) which clamps the shaft member (12).
