We have developed a new type of mobile robot system, in which robot executes a task under human assistance, aiming to improve reliability and rapidity of task performance. This robot system incorporates the human assistance for solving the unexpected problem arose during the task execution. The basic idea of the system is that in normal situation robot takes an autonomous action derected by the program, while in abnormal situation which means that some unexpected problem arose, human assists to help the robot action. As a system component, we have developed navigation command interpreter with intervention function to realize human assisted navigation conveniently. In this system, human assistance is also effectively utilized in the image information extraction for positioning error correction. We have demonstrated the feasibility of the system under the mock-up environment.