Abstract: The present disclosure illustrates a sectional door driving device including a power assembly, a chassis assembly and a driving assembly. The power assembly includes a motor, a gear set and a control unit, and the power assembly is fastened on a main chassis of the chassis assembly. The driving assembly includes two half-gears respectively in semicircular cylinder shape, and each of the two half-gears has a combination surface which is formed with an engagement assembly, and the two half-gears are engaged by the engagement assemblies thereof to form a circular gear to cover a shaft of a sectional door mechanism. The gear set includes an output gear configured to drive the circular gear and the shaft to rotate. The sectional door driving device can be separated from the shaft easily for repair, and the sectional door driving device can also be installed on the existing sectional door easily.