We have proposed contactless power transmission techniques for moving electric vehicles (EV) as method of resolving short cruising distance of EV. When we realize power feeding for moving EV, it will be possible to reduce in-vehicle battery and many drivers will utilize EV in relief for long-distance migration. In this research, we set up target efficiency of power transmission between feeding and receiving coil in system of contactless power transmission for moving EV on highway, and study length and width of feeding coils for achieving target efficiency.