A motor unit and a grill shutter driving device are disclosed. The grill shutter driving device according to an exemplary embodiment of the present inventive concept includes a body unit interposed between a plurality of grill shutters, a motor unit installed inside the body unit for generating driving power to drive the grill shutter, a control unit for controlling generation of driving power of the motor unit, and a connection unit for providing driving power of the motor unit to the grill shutter. The motor unit includes a plurality of coil units in which electric coil is rolled, a stator to be magnetized, a rotator having magnetism with a permanent magnet and rotating due to interference of the magnetization of the stator, wherein the plurality of coil units are separated with each other in a radial form with even number, and any one side of the mutually facing coil units includes electric coil rolled in, thereby forming an asymmetry coil structure.