To easily and firmly join piles without depending upon welding when they are joined together.

Tubular piles 1 are axially arrayed, a joining member 2 is caused to suspend a gap between the two piles 1 and 1 being arrayed, and common through-holes 4 are formed in the joining member 2 and the pile. A male screw rod 5a in which a nut 5c is threadedly fitted and being a central hole 5d formed from one end toward the other end side along an axis is formed through a through-hole 4. A slit 5e extending to the central hole 5d is formed in the other end of the male screw rod 5a and the male screw rod 5a is extended through the central hole. The slit 5e is spread by a pin 5b forcibly inserted from one end side of the rod 5a and by fastening the nut 5c threadedly fitted in one end of the male screw rod 5a, the pile 1 and the joining member 2 are tightly fastened against each other between the spread part and the nut.