To provide a lock mechanism for table legs or the like, wherein the constitution is simplified, the number of parts is reduced, and the manufacture is easy at a low cost, and which can be made compact, light-weight and uniform in quality, firmly supports the legs and provides a stable standing state, and also, by which the folding and standing operations of the legs can be performed smoothly and stably.

This lock mechanism is equipped with a bracket 7 which is attached to the rear surface of a top plate 1, and a leg joint 8 which is turnably connected to the bracket 7 and can connect a leg 21. On the bracket 7, engaging grooves 15 and 16 are provided in such a manner as to be apart. On the leg 21, an attachment 26 is turnably connected. On the attachment 26, an engaging rod 29 which can be engaged/disengaged with the engaging grooves 15 and 16 is provided. The attachment 26 is turnably urged to the bracket 7 side with a pivotal shaft as the center.