An electric bicycle includes two pedals, a motor, a battery providing power to the motor, a first detection member for detecting acceleration of the electric bicycle and trading acceleration of the pedals, and a controller. The controller receives the acceleration of the electric bicycle and the treading acceleration of the pedals from the first detection member, and then controls output of the motor and the battery. When the treading acceleration of the pedals is larger than the acceleration of the electric bicycle, the controller concludes that the resistance from outside to the electric bicycle increases, the controller increases output of the motor and the battery. When the treading acceleration of the pedals is smaller than the acceleration of the electric bicycle, the controller concludes that the resistance from outside to the electric bicycle decreases, the output of the motor and the battery is reduced.