The disclosed speed-change gear includes a fitting secured to the frame of a bicycle, a parallel link means having an outside link and an inside link whose one ends are pivotally connected to the fitting, a movable member pivotally connected to the opposite ends of the inside and outside links, a changeover frame rotatably secured to the movable member, which changeover frame carries a guide wheel and a tension wheel of a chain, and a cam means adapted to selectively move said movable member so as to shift the speed-change ratio by changing the position of said changeover frame to shift the chain to the desired step of a multi-step sprocket assembly of the bicycle. The cam means has a spring-biased cam rotatably mounted on a shaft connecting the outside link to the fitting, which cam rotates together with a wire-operated reel coaxially mounted on said shaft. The rotation of the cam actuates said parallel link means through a lever pivotally carried by a shaft connecting the inside link to the fitting.