Organic thin-film transistors (OTFTs) are being extensively studied for the next generation electronic devices, which will require cost reduction and flexibility. In this study, OTFTs with a double-gated structure were fabricated and their electric properties depending on main and complementary gate voltages were presented. Not only the drain currents, but also the surface potentials of pentacene films were remarkably modulated in accordance with the complementary gate field. A pMOS d-inverter circuit constructed with conventional and double-gated OTFTs was designed and fabricated, and the gain of the d-inverter measured at V (CG) = 0 V was approximately 2.8.