Construction is achieved that, when performing operation in order to maintain the position of a steering wheel after adjustment, is capable of reducing the operation torque that is applied to an adjustment lever 14 during the first half of the operation, and is capable of improving operability. Portions (virtual sliding-contact section lines M) of the drive-side cam surfaces 20a that can come in sliding contact with the driven-side continuous surfaces 24a when moving from a state in which the position of the steering wheel can be adjusted to a state in which the adjusted position can be maintained, are inclined toward one side in the circumferential direction at the time when the virtual sliding-contact section lines M overlap one end N1 in the circumferential direction of the driven-side continuous surfaces 24a. As a result, during operation, the areas of sliding contact between the drive-side cam surface 20a and the driven-side continuous surfaces 24a gradually increase from the inside end in the radial direction to the outside in the radial direction.