On the outer peripheral surface of a part of a tilt operation shaft between sidewalls of a steering column, a pair of left and right protrusions are disposed opposite to each other which protrude outward in the radial direction. The pair of protrusions include mutually facing side surfaces formed as slanted parts defining a truncated V shape in a plan view such that the slanted parts get closer to each other as extending in the circumferential direction of the tilt operation shaft. When the tilt operation shaft is rotated, parts of a spring come into contact with the slanted parts of the protrusions and become elastically deformed, thereby pulling hold end parts of the spring out of tilt holes in wall surface parts of a tilt bracket.