Disclosed is a multi-stage transmission which ensures that gear shifts are efficiently performed with a small number of component parts, smooth operations are performed with small forces, there are no loss of changeover time during gear shifts and no loss of the driving force, and the shift shock is small. The transmission has a driven gear shaft 12, in which are provided a first swing pawl member 25 engageable in a rotational direction with a first gear n1, a second swing pawl member 25 engageable in the rotational direction with a second gear n2 which is one step lower in reduction ratio, a third swing pawl member 24 engageable in the opposite rotational direction with the first gear n1, and a fourth swing pawl member 24 engageable in the opposite rotational direction with the second gear n2. A first cam rod 21 and a second cam rod 22 are provided which are slidable axially on and along the surface of an internal hole of the driven gear shaft 12. The first cam rod 21 is formed with a plurality of cam surfaces, which operate by movement thereof the second swing pawl member 25 and the third swing pawl member 24, while the second cam rod 22 is formed with a plurality of cam surfaces, which operate by movement thereof the first swing pawl member 25 and the fourth swing pawl member 24. Gear shift is carried out by moving the first and second cam rods 21, 22.