A drive device for an electric bicycle with a drive housing in which a hollow shaft is mounted which is connected to a chain wheel of a chain drive of the electric bicycle, a pedal crankshaft arranged coaxial to the hollow shaft and is couplable thereto, which crankshaft is connected to pedal cranks on each of its two ends and an electric motor the output of which can be coupled to the hollow shaft via a traction mechanism drive which drive means comprises a belt drive with a flexible traction mechanism in the form of a toothed belt, a flat belt, or a V-belt, or said drive means comprises a chain drive with a flexible traction mechanism in the form of a single or double roller chain.