A gutter block structure of the present invention has a configuration in which a vegetable fiber layer made of palm fibers or the like is integrally attached to an inner surface of a water-permeable concrete material, sidewall surfaces which serve as the inner surface are formed into a stepped shape, and a bottom surface which serves as the inner surface is formed into an irregular shape. Further, both the sidewalls are formed into a curved shape or S-shape. Thus, when a water channel is formed by the gutter block structures, the supply and drain of water between the water channel and the surrounding soil is enabled, the flow velocity of water can be reduced, and zones with different flow velocities can be provided. Thus, an environment at the water channel and around the water channel can be closer to a natural condition, and an environment for growing underwater creatures can be brought into a fairly good condition.