In this paper, we propose a method to detect moving obstacles from image data these are given from two cameras on the vehicle. Although the vehicle is moving, when it is possible to regard the position of the camera as being at a standstill, the variation of image data from the camera that is mounted on the vehicle is caused by target motion. Therefore this paper shows a system that is keeping a suspected stationary state of the position of the camera by means of two cameras and a moving structure, and detects moving obstacles.