Abstract: An elevating mechanism includes a frame supported above and in parallel to a base, the base and the frame are stably coupled together by a pair of lazy tong constructions, the pair of lazy tong constructions include four pivot axles defining a plane which is parallel to the base and the frame, a block secured on each of the pivot axles for engaging with two parallel bolts, the end portions of the bolts have outer thread of different screw directions such that the blocks are caused to move toward each other or to move away from each other when the bolts are rotated, the lazy tong constructions can thus be extended or retracted when the blocks are moved toward each other or moved away from each other.