In a rack bar and a steering device using the same, an endmost tooth bottom for reducing a stress exerted on a first forging die during die forging of a rack tooth molding part is formed on the endmost side of a plurality of tooth bottoms. Specifically, the endmost tooth bottom is formed so that a depth thereof is less than a depth of an ordinary tooth bottom by a difference. This reduces an amount of flow of a material of the rack bar during formation of the endmost tooth bottom by an amount commensurate with the difference. As a result, the stress exerted on the first forging die can be reduced, and occurrence of heat checking in the first forging die can be suppressed.