PURPOSE: To dispense with a chain by fitting a bevel gear type bent drive gear to a lower bracket support shaft, transferring the pedal foot force to a rear bevel gear type bent auxiliary drive gear via a spindle, and rotating a free wheel.

CONSTITUTION: A bevel gear type bent drive gear 43 receives the pedal foot force from a lower bracket support shaft 4 and transfers rotation to an auxiliary drive gear 6. The rotation of the gear 6 is transferred to a polygonal drive spindle 11, a bevel gear type bent driven gear 9 is rotated, and an auxiliary driven gear 10 is rotated. The rotation of the gear 10 is transferred via a gear shaft fitted to a free wheel and a one-way latch, and the free wheel is rotated forward. The pedal foot force is transferred to a rear wheel without requiring chain drive, and performance is improved.