To reduce play in rotary direction in a connecting area between first and second fork stems during handlebar operation by connecting together the first and second fork stems to permit relative movement in the axial direction while preventing relative rotation by engagement of a key with a key hole of a width narrower than the width of the key in a free state including plate springs.

An elliptic slot 52 to be a key hole for a connecting area 45 is formed in the lower portion of a first fork stem 41 in the axial direction with a width slightly smaller than a free state width of an anti-rotation key 51 including plate springs constituting the connecting area 45, with the key 51 made to engage with the elliptic slot 52. The first fork stem 41 and a second fork stem 42 are connected together at the connecting area 45 to permit relative movement in the axial direction while preventing relative rotation. Thus, play is reduced during handlebar operation in the rotary direction in the connecting area 45 between the first fork stem 41 and the second fork stem 42.