To produce inexpensively a stable support leg for a double floor by developing a caulking method which combines strong joint strength and the reduction of producing cost.

A base plate 3 is provided with circular inclined surface 14, circular inner circumferential surface 15, and circular flange 16 installed in connection, the end of a column support pipe is inserted into the circular inner circumferential surface 14, and a curling portion which clamps the end of pipe column 2 with the circular inner circumferential surface 15 and the circular flange 16, is formed by folding back the circular flange 16 upwards. And at the same time, the curling portion is spread so as to make contact with the circular inclined surface 14, and the caulking portion which is formed by crushing to caulk the curling portion and the circular inclined surface 14 in one, connects the column pipe with the base plate 3, thereby producing the support leg for double floor.