Abstract: A rainwater guide device is coupled to an outer side of the rail portion to be adjacent to the rainwater drainage hole, wherein the rainwater guide device includes a rainwater receiving portion defined at one closed side end thereof to receive the rainwater from the drainage hole and having an open top, and a rainwater outlet defined at the other open side end thereof, wherein the bottom plate includes a tilted plate tilted downwards from the rainwater receiving portion to the rainwater outlet in a longitudinal direction thereof, and two rainwater guide plates, each guide plate having a first side coupled to the tilted plate and a second side coupled to a corresponding longitudinal side plate, wherein each of the rainwater guide plates is tilted downwardly from the second side to the first side.