PURPOSE: To improve a display characteristic of an active matrix device.

CONSTITUTION: An intermediate-pulse having a middle potential between a selection potential and a nonselection potential is applied more than one time during a nonselection period with respect to a gate of a switching thin film transistor provided on every picture element of the active matrix device. Thus the pulse with an intermediate potential is applied during a nonselection period, so heat generation at many carriers in a channel portion of the thin film transistor is suppressed and then a drain current at an off-time is suppressed to low.