In this paper, a novel path planning and a novel tracking control way of wheeled mobile robot is proposed. Since wheeled mobile robots have nonholonomic constraint, it is impossible to track an arbitrary trajectory at an arbitrary speed. In the conventional ways, the path that the robots can track and that fills the requirement like the collision avoidance etc. is planned. In addition tracking control aims to make the robot follow accurately this path. However, when the robot swerves from the trajectory, it is necessary to plan the trajectory again in such methods. According to the planning way, such a trouble can be raised with the action of the robot because the amount of calculation is huge. Then, this paper aims to track the trajectory, which is assumed not to be able to track because of nonholonomic constraint, in a constant permissible error range. In addition, it is proposed that a novel tracking control method by which the robot can return to the trajectory when the robot swerves from it. Besides, the way to give the commands taking the performance of the actuator into consideration is proposed.