PURPOSE: To provide the low unnecessary-radiation image display device as a computer display.

CONSTITUTION: A horizontal deflection circuit 17 is composed of a bi-directional scanning system and a vertical deflection circuit 18 is composed of a staircase system; and the current flat parts are provided at the horizontal deflection current and the vertical deflection current and the phase relation between the horizontal deflection current and vertical deflection current is so set that when one is flat, the other is not. The time base of a video signal is inverted at intervals of a horizontal scanning line by an A/D converter 6, switch circuit 7 and 10, line memories 8 and 9, a D/A converter 11, and a digital control circuit 16 to make a display. Consequently, no horizontal flyback pulse is generated and the low unnecessary-radiation image display device is obtained.