PURPOSE: To obtain a display picture of good quality without generating a flicker and a ghost phenomenon by providing a phase difference so that the phase of grid signals is delayed in relation to the phase of anode signals.

CONSTITUTION: The phase of GORVONTIM is delayed from that of ADRVONTIM so that a phase difference is generated between grid signals G0, G1... and anode signals P1, P2... in timing. Even when an anode signal P1 is made on and other anode signals P2, P3 generate differential pulses, fluorescent discharge lamps 61W6m are lighted with no flicker because all grid signals G0WGm are made off. Since the grid signal G0 is still on at the time when the anode signal P1 is made off, it is lowered to a non-lighting level before the grid signal G1 is made on next time, thereby no ghost phenomenon appears at a dot corresponding to the anode signal P1 when a dot corresponding to the grid signal G1 is lighted.