PURPOSE: To provide a high performance two wheeler having a high energy efficiency by amplifying the driving force.

CONSTITUTION: In a high performance two wheeler, a rotating assistor connected to a rear wheel hub 34 engages an eccentric power gear 22 with a large diameter with a drive gear 21 with a small diameter driven by an input shaft 15b and connects the eccentric power gear to an epicyclic gear 28 with a diameter smaller than it, whereby the torque of the drive gear is amplified and transmitted to the epicyclic gear, and the amplified output is transmitted from the epicyclic gear to the rear wheel hub through a sun gear 24 and an output shaft 15c.