The electronics fields face serious problems associated with electric power; these include the development of ecologically friendly power-generation systems and ultralow-power-consuming circuits. Moreover, there is a demand for developing new power-transmission methods in the imminent era of ambient electronics, in which a multitude of electronic devices such as sensor networks will be used in our daily life to enhance security, safety and convenience. We constructed a sheet-type wireless power-transmission system by using state-of-the-art printing technologies using advanced electronic functional inks. This became possible owing to recent progress in organic semiconductor technologies; the diversity of chemical syntheses and processes on organic materials has led to a new class of organic semiconductors, dielectric layers and metals with excellent electronic functionalities(1-5). The new system directly drives electronic devices by transmitting power of the order of tens of watts without connectors, thereby providing an easy-to-use and reliable power source. As all of the components are manufactured on plastic films, it is easy to place the wireless power-transmission sheet over desks, floors, walls and any other location imaginable.