It is an object of the present invention to provide a rear wheel steering device of which the weight is not added to unsprung weight, and which can steer right and left rear wheels independently of each other. The rear wheel steering device includes a first rod connected to the left rear wheel, a first driving portion configured to axially move the first rod, a second rod connected to the right rear wheel, and a second driving portion configured to axially move the second rod. A single housing supports the first rod, the first driving portion, the second rod, and the second driving portion.