Cable laying structure and wind power generation system

A cable laying structure is provided with: a cable; a plurality of buoys that align in the length direction of the cable, are attached to portions of the cable to which the buoys are to be attached, and allows the cable to float in water; and a wire that is attached to the portions of the cable to which the buoys are to be attached and applies a tension opposed to the buoyancy of the buoys to the cable, thereby maintaining, in an arch shape, the shape of the portions to which the buoys are to be attached. The buoyancy of the buoy disposed on an end side of the portions to which the buoys are to be attached, in the length direction of the cable, is smaller than the buoyancy of the buoy disposed on the center side of the portions to which the buoys are to be attached.