Assisting device for shift control unit of bicycle transmission

PURPOSE: A bicycle speed change assist device is provided to secure the reliability of gear shift by accurately releasing the engagement between a pole and a sun gear. CONSTITUTION: A bicycle speed change assist device comprises a plurality of compression members which are arranged in a pole control ring(15) of a speed change device and move in and out of the pole control ring. A carrier(20) is installed outside the pole control ring, and spline grooves(27) are formed on the inner surface of the carrier. As the carrier is rotated, the spline groove presses the compression members and poles(12,13) are restrained, thereby releasing the engagement between the pole and sun gears(23,24).