A cable winding conversion device is provided that enables relatively easy placement on a frame such as a bicycle frame between a pair of cables. The cable winding conversion device basically includes a base member, a first winder, a second winder, a first cable mounting portion, and a second cable mounting portion. The base member is configured to be mounted to a frame. The first and second winders are rotatably mounted to the base member to wind first and second inner wires of the first and second cables. The second winder has at least a portion with a winding radius larger than the first winder. The first cable mounting portion directs the first cable. The second cable mounting portion directs the second cable. The second cable mounting portion includes a cable receiving opening that is directed toward a rotation center of the winders.