PURPOSE: To generate a parabolic voltage of a vertical period and a parabolic voltage of a horizontal period used for the correction of left and right pincushion distortion and vertical pincushion distortion 'a cathode ray display device through digital control.

CONSTITUTION: One vertical or horizontal period in a synchronization state is divided into a prescribed number of sections equally, and a digital level is set at every divided section through the adjustment of an adjustment signal generating section 3. A signal based on the adjustment is outputted by a control circuit 4. A digital output of the control circuit 4 is D/A-converted by a D/A converter circuit 6. An analog output by the D/A conversion is changed stepwise at every section and the envelope line becomes a voltage waveform to form a parabola shape. Then a vertical or horizontal parabolic voltage is obtained by passing a D/A conversion output through an LPF 7. The vertical or horizontal parabolic voltage is used similarly to the case with a conventional method.