Human-machine cooperative systems have been proposed. Most of them consider carrying, positioning and assembling tasks. Precise tracking tasks are also required in factories. However, an assist system for tracking task has not been studied well. In this paper, we aim to realize the humanmachine system that assists a tracking task. In order to achieve the goal, the virtual friction field is proposed. Isotropic and anisotropic friction fields are presented and they are applied to the rotating object which should be tracked. The tracking task experiments are carried out and it is shown that the virtual guide of the friction improves the tracking performance effectively.