A steering device comprising: a steering column having a configuration in which a front section of an outer column (11a, 11b) is set with respect to a rear section of an inner column so that a relative displacement therebetween can be applied in an axial direction, the inner column being arranged at a relatively front side, the outer column (11a, 11b) being arranged at a relatively rear side; a support bracket including a pair of support plates which sandwich the front section of the outer column (11a, 11b) from both sides thereof in a width direction, the support bracket being installable on a vehicle body; and an adjusting rod inserted through a first through hole (21a, 21b) formed in the front section of the outer column (11a, 11b) and second through holes formed in the support plates in the width direction, characterized in that a slit is formed in the front section of the outer column (11a, 11b) and extends at least in the axial direction of the outer column (11a, 11b), a pair of clamp parts (38, 38a) are provided adjacent to the slit and are arranged on portions on both of the sides of the outer column (11a, 11b) in the width direction such that the clamp parts (38, 38a) are bent when an interval between inner surfaces of the pair of support plates is reduced to elastically sandwich an outer circumferential surface of the inner column, a first surface (49a, 49c) and a second surface (49b, 49d) are provided on both lateral surfaces of the outer column (11a, 11b) in the width direction and are spaced apart from each other in a vertical direction such that each of the clamp parts (38, 38a) is arranged therebetween, and such that torque acting on the outer column (11a, 11b) via the first and second surfaces (49a, 49b, 49c, 49d) is transmitted to inner surfaces of the support plates, at least one of the first surface (49a, 49c) and the second surface (49b, 49d) is provided on a lateral surface of a reinforcing plate provided on the outer column (11a, 11b) in the width direction and which extends in the width direction in a state in which the reinforcing plate covers the pair of clamp parts (38, 38a), the first through hole (21a, 21b) is provided between a distal end section of the clamp part (38, 38a) and the reinforcing plate, a pair of joining parts (43a, 43b) extending in the vertical direction are provided on both end sections of the reinforcing plate in a forward and rearward direction, a bridge part is constituted of the pair of joining parts (43a, 43b) and the reinforcing plate, and a substantially U-shaped gap is provided between the bridge part and the clamp part (38, 38a). a steering column having a configuration in which a front section of an outer column (11a, 11b) is set with respect to a rear section of an inner column so that a relative displacement therebetween can be applied in an axial direction, the inner column being arranged at a relatively front side, the outer column (11a, 11b) being arranged at a relatively rear side; a support bracket including a pair of support plates which sandwich the front section of the outer column (11a, 11b) from both sides thereof in a width direction, the support bracket being installable on a vehicle body; and an adjusting rod inserted through a first through hole (21a, 21b) formed in the front section of the outer column (11a, 11b) and second through holes formed in the support plates in the width direction, characterized in that a slit is formed in the front section of the outer column (11a, 11b) and extends at least in the axial direction of the outer column (11a, 11b), a pair of clamp parts (38, 38a) are provided adjacent to the slit and are arranged on portions on both of the sides of the outer column (11a, 11b) in the width direction such that the clamp parts (38, 38a) are bent when an interval between inner surfaces of the pair of support plates is reduced to elastically sandwich an outer circumferential surface of the inner column, a first surface (49a, 49c) and a second surface (49b, 49d) are provided on both lateral surfaces of the outer column (11a, 11b) in the width direction and are spaced apart from each other in a vertical direction such that each of the clamp parts (38, 38a) is arranged therebetween, and such that torque acting on the outer column (11a, 11b) via the first and second surfaces (49a, 49b, 49c, 49d) is transmitted to inner surfaces of the support plates, at least one of the first surface (49a, 49c) and the second surface (49b, 49d) is provided on a lateral surface of a reinforcing plate provided on the outer column (11a, 11b) in the width direction and which extends in the width direction in a state in which the reinforcing plate covers the pair of clamp parts (38, 38a), the first through hole (21a, 21b) is provided between a distal end section of the clamp part (38, 38a) and the reinforcing plate, a pair of joining parts (43a, 43b) extending in the vertical direction are provided on both end sections of the reinforcing plate in a forward and rearward direction, a bridge part is constituted of the pair of joining parts (43a, 43b) and the reinforcing plate, and a substantially U-shaped gap is provided between the bridge part and the clamp part (38, 38a).