In executing the opposing common inverse drive in an active matrix-type semiconductor display device, a gate bias is suppressed to be comparable with that of the conventional inverse drive to avoid a range in which the off current jumps up and, hence, to suppress the leakage of the stored electric charge, thereby to maintain an ON/OFF margin of the pixel TFTs. The gate bias applied to the pixel TFT is maintained to be near the customarily employed voltage to maintain a gate breakdown voltage, and the electric power is consumed in a decreased amount by the drive circuit as a whole, thereby to provide a novel drive circuit. In the semiconductor display device, a tristate buffer is used for a gate signal line drive circuit, and different buffer potentials are applied depending upon a frame in which the opposing common potential assumes a positive sign and a frame in which the opposing common potential assumes a negative sign, thereby to maintain an ON/OFF margin of the pixel TFTs. The voltage amplitude is decreased during the opposing common inverse drive.