A steering column device, comprising: a lower jacket having a cylindrical shape and arranged in a vehicle longitudinal direction; a slit penetrating through a cylinder wall of the lower jacket along a cylinder-axis direction of the lower jacket; a pair of clamp parts formed so as to stand on both marginal parts of the slit; an upper jacket having a cylindrical shape and inserted into the lower jacket movably in the cylinder-axis direction; a lock plate fixed on an outer circumferential face of the upper jacket and inserted into the slit movably in the cylinder-axis direction, the lock plate having a plurality of lock holes opened along the cylinder-axis direction successively; an operating shaft arranged so as to penetrate through the pair of clamp parts; an operating lever arranged on the operating shaft to allow the operating shaft to be rotated about an axis of the operating shaft; a cam member arranged on the operating shaft so as to rotate together with the operating shaft; characterised by a lock supporting shaft arranged in the pair of clamp parts, in parallel with the operating shaft; a lock member rotatably supported by the lock supporting shaft while cooperating with the cam member, the lock member being inserted into and removed from the lock hole in association with the rotating operation of the operating shaft; a pair of stoppers formed so as to stand radially outward from respective ends of the lock plate in the cylinder-axis direction and adapted so as to be capable of abutting on the lock member, thereby defining a telescopic-position adjustment range when the upper jacket moves in the cylinder-axis direction; and a guide member made of resin material and arranged on the lock plate so as to extend in parallel with the cylinder-axis direction, the guide member including a pair of guide rails between which the lock member is pinched in the axial direction of the lock supporting shaft, wherein the rotating operation of the operating lever about an axis of the operating lever in a fastening direction allows an interval between the pair of clamp parts to be narrowed, whereby the upper jacket is fastened to the lower jacket. a lower jacket having a cylindrical shape and arranged in a vehicle longitudinal direction; a slit penetrating through a cylinder wall of the lower jacket along a cylinder-axis direction of the lower jacket; a pair of clamp parts formed so as to stand on both marginal parts of the slit; an upper jacket having a cylindrical shape and inserted into the lower jacket movably in the cylinder-axis direction; a lock plate fixed on an outer circumferential face of the upper jacket and inserted into the slit movably in the cylinder-axis direction, the lock plate having a plurality of lock holes opened along the cylinder-axis direction successively; an operating shaft arranged so as to penetrate through the pair of clamp parts; an operating lever arranged on the operating shaft to allow the operating shaft to be rotated about an axis of the operating shaft; a cam member arranged on the operating shaft so as to rotate together with the operating shaft; characterised by a lock supporting shaft arranged in the pair of clamp parts, in parallel with the operating shaft; a lock member rotatably supported by the lock supporting shaft while cooperating with the cam member, the lock member being inserted into and removed from the lock hole in association with the rotating operation of the operating shaft; a pair of stoppers formed so as to stand radially outward from respective ends of the lock plate in the cylinder-axis direction and adapted so as to be capable of abutting on the lock member, thereby defining a telescopic-position adjustment range when the upper jacket moves in the cylinder-axis direction; and a guide member made of resin material and arranged on the lock plate so as to extend in parallel with the cylinder-axis direction, the guide member including a pair of guide rails between which the lock member is pinched in the axial direction of the lock supporting shaft, wherein the rotating operation of the operating lever about an axis of the operating lever in a fastening direction allows an interval between the pair of clamp parts to be narrowed, whereby the upper jacket is fastened to the lower jacket.