Recently, as more robots work in the same space as men, they are desired not to make humans stressful. The purpose of this study is to develop a mobile robot passing people smoothly. As humans move according to their intentions, we estimated them. Concretely, we estimated whether they are trying to avoid a robot through the trajectory of them. Then, we implemented an algorithm of estimating humans’ intention by tracking their legs. Based on the estimation and the social force model, the robot makes a path plan.