A bicycle includes an auxiliary power unit for regenerating electric energy even with no braking operations. A power-assisted bicycle includes a controller for detecting a torque value of a pedaling torque applied to a crankshaft for controlling an output of a brushless motor according to the torque value detected. A power transmitting member outputs the pedaling torque applied to the crankshaft to a rear wheel with a clutch unit for permitting an output of a driving force of the brushless motor to the rear wheel, but not an output of power from the rear wheel to the brushless motor. A selector selects whether or not to permit transmission of power from the rear wheel to the brushless motor. The clutch unit includes a lock-up ratchet for selectively permitting an output of power from the rear wheel WR to the brushless motor according to an operation of the selector.