To provide a transmission device for an automobile and motorcycle, which is improved to be compact with high efficiency by using magnetic power.

The rotation of a prime mover shaft rotates a power generating rotor (3) and a motor stator (1) through a gear (4). The power generated by a generator 3 is converted to DC current by a commutator (5) and passes through a motor (1). By integrating the generator with the motor, torque is transmitted with high efficiency by the resistance by the rotation of the power generating coil (3) and the magnetic power generated at the motor stator (1). By giving the rotation from the prime mover shaft to a motor, a rotor (2) is guided and rotated by the magnetic power of the stator coil (1) even if a large load is applied to a drive shaft. The load applied to the drive shaft is transmitted to the prime mover, thus it is possible to control the output of the prime mover positively.