PURPOSE: To correct the parallelogrammic distortion on a screen by adding a vertical saw tooth wave component to a horizontal deflecting circuit to continuously change the phase to the horizontal synchronizing signal of the output pulse of a horizontal oscillating circuit in each vertical period.

CONSTITUTION: When a vertical deflecting saw tooth wave current flows to a vertical deflecting yoke VDY, a saw tooth wave voltage is generated at the connection point of resistances RA and RB. This voltage has the DC component cut by a capacitor C7 and is inputted to an operational amplifier IC2. The output of the amplifier IC2 is inputted to a horizontal AFC circuit, and the output is not a DC but has a vertical saw tooth wave component. The phase of the pulse at an output terminal (OUT) of the horizontal oscillating circuit is continuously changed from the top to the bottom of the screen in accordance with this vertical saw tooth wave component, thus correcting the parallelogrammic distortion.