This paper proposes a method to allocate multiple cameras to a better or the best positions. In RoboCup Small Size League(SSL), two or more cameras are used, and we have to decide the layout of them at the venue. This paper gives a criterion which minimizes the risk, for example, the occlusion of a ball by robots, and solves it by using Fletcher-Reeves conjugate gradient algorithm. Experimental result shows the effectiveness of the proposed method.