In this paper, we propose a system to help learners improve the running form by the motion-capture system. We can capture the running form along with the time processing by this system. The system assumes the ideal running form that keeps the stable style. An ideal form is given by an expert. The system detects and represents the difference between learner's form and pre-defined ideal form. In order for that, the system compares the current form with an ideal form that is represented by three-dimensional values. In our system, an ideal running-form is previously defined. The system also presents an advice of improving the running-form for learners.