A position adjustment device of a steering wheel, the position adjustment device comprising: a cylindrical steering column; a displacement bracket which is fixedly provided in a portion of the steering column, and is formed with a through hole on a column side so as to pass through the displacement bracket in a width direction; a steering shaft which is rotatably supported inside the steering column, and includes a rear end portion which protrudes from a rear end opening of the steering column so as to support and fix the steering wheel; a support bracket which is supported by a vehicle body, includes left and right supporting plate portions which interpose the displacement bracket from both sides in the width direction, and is formed with through holes on a vehicle body side in portions of the supporting plate portions corresponding to each other; an adjustment rod which is inserted into the through holes on the vehicle body side and the through hole on the column side in the width direction; a nut which is threadedly fixed to one end portion of the adjustment rod in an axial direction thereof; a cam mechanism which includes a driving cam and a driven cam, and is configured to increase and decrease an axial dimension thereof in accordance with a rotation of the driving cam with respect to the driven cam so as to increase and decrease a distance between the left and right supporting plate portions; and an adjustment lever which is connected to the driving cam, wherein the driving cam is supported by a portion close to one axial end of the adjustment rod such that an axial displacement of the driving cam is inhibited, and is rotatable based on an operation of the adjustment lever, wherein the driven cam is engaged with the through hole on the vehicle body which is provided on one of the left and right supporting plate portions, and is supported by an intermediate portion of the adjustment rod in the axial direction so as to be displaceable in the axial direction, wherein at least one of the through holes on the vehicle body side and the through hole on the column side is configured as a long hole which is long in a direction in which a position of the steering wheel is adjustable, characterized in that the portion close to one axial end of the adjustment rod is provided with a step forming surface (36, 36a, 42) which faces one side of the axial direction, and wherein the driving cam is sandwiched between the step forming surface (36, 36a, 42) and the nut. a cylindrical steering column; a displacement bracket which is fixedly provided in a portion of the steering column, and is formed with a through hole on a column side so as to pass through the displacement bracket in a width direction; a steering shaft which is rotatably supported inside the steering column, and includes a rear end portion which protrudes from a rear end opening of the steering column so as to support and fix the steering wheel; a support bracket which is supported by a vehicle body, includes left and right supporting plate portions which interpose the displacement bracket from both sides in the width direction, and is formed with through holes on a vehicle body side in portions of the supporting plate portions corresponding to each other; an adjustment rod which is inserted into the through holes on the vehicle body side and the through hole on the column side in the width direction; a nut which is threadedly fixed to one end portion of the adjustment rod in an axial direction thereof; a cam mechanism which includes a driving cam and a driven cam, and is configured to increase and decrease an axial dimension thereof in accordance with a rotation of the driving cam with respect to the driven cam so as to increase and decrease a distance between the left and right supporting plate portions; and an adjustment lever which is connected to the driving cam, wherein the driving cam is supported by a portion close to one axial end of the adjustment rod such that an axial displacement of the driving cam is inhibited, and is rotatable based on an operation of the adjustment lever, wherein the driven cam is engaged with the through hole on the vehicle body which is provided on one of the left and right supporting plate portions, and is supported by an intermediate portion of the adjustment rod in the axial direction so as to be displaceable in the axial direction, wherein at least one of the through holes on the vehicle body side and the through hole on the column side is configured as a long hole which is long in a direction in which a position of the steering wheel is adjustable, characterized in that the portion close to one axial end of the adjustment rod is provided with a step forming surface (36, 36a, 42) which faces one side of the axial direction, and wherein the driving cam is sandwiched between the step forming surface (36, 36a, 42) and the nut.