PURPOSE: To easily assemble a furniture and the like by energizing a slide body with an elastic body, providing the slide body so as to project and retreat the extreme end part through a window part, and enabling an insert connecting body to insert and lock the extreme end part of the slide body into a cylindrical body to be connected having a lock part.

CONSTITUTION: The fitting body 16 of a cylindrical body 3 to be connected is fitted to the fitting hole of a table, and the end part of the outside body 4 of an insert connecting body 2 is press-fitted to the fitting hole of a leg member. When the insert connecting body 2 is inserted into the cylindrical body 3 from the extreme end on a tapered side of the outside body 4, the tapered part of the extreme end part projecting from the window part 6 of a slide body 5 is pressed by the wall of the cylindrical body 3, the slide body 5 retreats from a spring, and the extreme end is flush with the side of the outside body 4. When the connecting body 2 is further pushed in and the whole extreme end of the slide body 5 is positioned in a box lock part 14, it is released from pressure, the extreme end is projected from the window part 6, and it is received in the box lock part 14. In this condition, the connecting body 2 is connected to the cylindrical body 3.