This paper presents a remote control between a haptic feedback control stick and a wheel of a two-parallel-wheeled rover. It is well-known that the operator's operability was improved largely by haptic information reproduced on the stick using the bilateral control. This haptic information corresponds to disturbance force/torque applied to the wheel of the rover. When the disturbance is estimated using the disturbance observer (DOB), its estimated value includes not only an external force, viscous resistance, Coulomb frictional force, and a force by a modelling error, but also a restoring force. The restoring force is a force occurring when an operating-operated robot system is synchronized by a position control. It often becomes a problem of the bilateral control using two robots with a dynamically-different structure. Particularly, our experimental system in this paper has a very large dynamical difference. In other words, there exists a fairly-large time delay between them. The DOB of the operating robot estimates a value including this restoring force. Intuitively, this seem to prevent the operator from feeling sensitively other forces applied to the wheel such as the external force. However, on the same time the authors think this restoring force is very important for the operator to know situations of the remote rover, e.g., whether it drives with the speed given as a command value or not. In this paper, we proposes a positional gain adjusting bilateral control method in order not to prevent the restoring force from feeling the external force and so on. The proposed method was experimented for verification. Experimental results were discussed and evaluated comparing to the following two cases: one is when a positional gain of the operating robot is reduced as the difference increases, and the other is when that of the operated robot is enhanced contrarily as the difference increases.