To shrink reflecting waves in relation to waves in a broad wavelength are covering from short to long waves by killing and reducing approaching waves well with reflecting waves generated by the body of a floating wave absorbing dyke and to put the dyke into widespread use as a wave-absorbing structure.

In a low-reflection floating wave absorbing dyke, multiple wave- reflecting boards 3a, 3b are arranged through poles 4 with a clearance in the horizontal direction from the side of the body 1 of a floating wave absorbing dyke. The relative physical relationship of the reflecting boards 3a, 3b is determined so that the distance of the lower reflecting board 3b of the multiple reflecting boards 3a, 3b from the side of the body 1 may be longer than that of the immediate upper reflecting board 3a from the side of the body 1.