It is necessary for a blind person to know the locations of the pedestrians or moving objects around him/her on a walk road for his/her safe walking. This paper proposes a system for detecting pedestrians or moving objects in front of a person on a walk road by a camera mounted on his/her body. The system judges if a moving object in front of the person is going to hit him/her in the near future by analyzing the motion vectors acquired on the camera images. In case there is a fear of hit, the system tells it to the person by sound. In this way, the proposed system helps safe walking of a blind person. Some experimental results are shown with discussion.