Steering system

A steering system comprising:

• an inside member configured to extend along an axis and to have a steering wheel mounted on a first end side in an axial direction;
• an outside member comprising a guide tube part into which the inside member is inserted to support the inside member to be movable in the axial direction, and a holding part which is located on the first end side in the axial direction with respect to the guide tube part and in which a slit extending in the axial direction is formed;
• and
• a telescopic adjustment mechanism configured to switch between a locked state in which an interval of the slit is reduced and movement of the inside member relative to the outside member is regulated by the holding part and an unlocked state in which the interval of the slit is increased and the movement of the inside member relative to the outside member is allowed,
• wherein an inner circumferential surface of the guide tube part comprises:
• support surfaces that slidably support an outer circumferential surface of the inside member, and
• flanks that are located on the same circumference as the support surfaces and are separated from the outer circumferential surface of the inside member in a radial direction.