To provide an energy absorber capable of reducing the wear of water discharge pipes in a tailrace of steep gradient, and damages of rivers and structures to which effluent is drawn off.

A plurality of energy absorber tanks 5 having each inner circumferential surface of circular section are successively connected via water discharge pipes 4 installed along the gradient of inclined surfaces so that energy of the flow-in water is absorbed by the circulation thereof along the inner circumferential surfaces in each energy absorber tank 5. Since the energy is absorbed step by step in each energy absorber tank 5, and no abrupt change in the flow direction generating any shocks is generated in each energy absorber tank 5, and no excessive shocks are generated in the energy absorber tanks 5 themselves. New entrainment of air in water passing through the energy absorber tanks 5 is suppressed as much as possible. As a result, breakage of the water discharge pipes or energy absorber themselves can be prevented, and damages of the rivers and structures to which effluent is drawn off can be prevented.