Disclosed is an electric-bicycle driving apparatus. The electric-bicycle driving apparatus includes a speed-change mode operator to output a low-speed or high-speed mode signal, a controller to receive the low-speed or high-speed mode signal from the speed-change mode operator and to output a first or second control-signal corresponding to the low-speed or high-speed mode signal, a generation-signal provider to provide a generation-signal output from a generator, and a motor-driver operating-signal regulator to receive the first or second control signal when the speed-change mode operator outputs the low-speed or high-speed mode signal, to regulate a level of the generation-signal output from the generation-signal provider and to provide the resulting signal to a motor driver that drives a motor, the motor-driver operating-signal regulator providing a lowered level of generation-signal to the motor driver that is operated upon receiving power of a battery, and cutting off an abnormal signal from the motor driver.