To facilitate taking-out of a buffer body by embedding a wire in an elastic body which is used as the buffer body between caissons, extending both ends of the wire outward out of the elastic body, and pulling out the wire to form a space in the elastic body.

A buffer body 10 consists of an elastic body 11 which is rectangular parallelopiped and made of rubber, a wire 12 for pulling up which is embedded in the elastic body 11, and a wire 13 for rupture. Next, when a bank is constructed by caissons, the buffer body 10 is provided between caissons in a condition in which it is compressed. Then, when the buffer body 10 is removed, a hook 13a is connected with a crane to pull up the wire 13. The wire 13 in the elastic body 11 is pulled out of the elastic body 11 while rupturing the wall of the elastic body 11. Consequently, a space is formed in the elastic body 11, internal stress is reduced, and friction resistance between the caisson and it is reduced. Furthermore, a hook 12a is connected with the crane to pull out the elastic body 11 from between the caissons. As a result, it is possible to take out the buffer body easily.