A steering device includes a column housing encapsulating a steering shaft and enabling a posture change, a bracket located adjacent to the column housing, and a tensioner mechanism being between the column housing and the bracket, and pressing the column housing and the bracket. The tensioner mechanism includes a casing provided in the column housing or the bracket, a tensioner main body being provided in the casing, and being movable in a direction intersecting a facing direction of the column housing and the bracket, and a biasing member biasing the tensioner main body. The tensioner main body includes a first surface facing toward the column housing, and a second surface facing toward the bracket. The first surface and the second surface are configured to be in a tapered shape in which a space therebetween becomes narrower as closer to a lower side of a biasing direction.