In recent years, several low-price 3D laser scanners are being brought to the market and 3D laser scanning has been widely used in many applications. For example, 3D modeling of architectural structures and digital preservation of cultural heritages are typical applications for 3D laser scanning. Despite of the development of light-weight and high-speed laser scanners, complicated measurement procedure and large measurement time are still heavy burden for the widespread use of laser scanning. We have proposed a robotic 3D scanning system using multiple robots named CPS-SLAM, which consists of parent robots with a 3D laser scanner and child robots with corner cubes. This system enables to perform 3D laser scanning without complicated post-processing procedures such as ICP, and large-scale 3D models can be acquired by an on-board 3D laser scanner from several positions determined precisely by the localization technique named Cooperative Positioning System, CPS. This paper proposes an automatic planning technique for an efficient laser measurement for the CPS-SLAM system. By planning a proper scanning strategy depending on a target structure, it is possible to perform laser scanning efficiently and accurately even for a large-scale environment. Proposed technique plans an optimal scanning strategy automatically by taking several criteria, such as visibility between robots, error accumulation, and efficient traveling, into consideration. We conducted computer simulation and outdoor experiments to verify the performance of the proposed technique.