In this paper, we propose the recognition methods by image processing using 2D or 3D CAD. In the case of 2D CAD, an object is recognized by comparing five characters calculated from the center of gravity and contour. In the case of 3D CAD, there are two recognition methods. Firstly 3D CAD figure is transformed into 2D CAD figures. And an object is recognized by comparing 2D CAD figures with inputted images. Secondly the three dimensional coordinates of vertexes on an object are calculated from the images taken from some cameras and compared 3D coordinates with those of 3D CAD figures and recognized the sort of an object.