In a display device in which each pixel includes a thin film transistor which is turned on in response to a scanning signal from a gate signal line, and an electrode to which a video signal from a drain signal line is supplied through the thin film transistor, the scanning signal allows a voltage level thereof which turns on the thin film transistor to have a valley portion which decreases the voltage level in a midst portion thereof, and the decreased voltage level of the valley portion is set to a value which is equal to or more than a voltage level which turns off the thin film transistor.