We propose an automatic color calibration method for a multi-camera system by using colors of objects in the common view of the multiple cameras. We assume that at least one camera has already been calibrated a prior . Then, by comparing the output of calibrated camera and un-calibrated camera, the color characteristic of un-calibrated camera can be estimated in our proposed method. In this paper, we evaluated the proposed method by using two cameras as preliminary experiments. The experimental result shows the effectiveness of our proposed method.