PURPOSE: To obtain the inexpensive device capable of readjustment on a user side by using an output of a communication circuit so as to control a memory reader/writer thereby reading and writing a content of a correction data memory.

CONSTITUTION: A digital dynamic convergence(DDC) device 10 driving a color slurring correction coil 1 consists of a correction data memory 2, a D/A converter 3, a zone address generator 4 and a memory reader writer 11 or the like. The memory reader/writer 11 reads/writes the content of the correction data memory 2 and the zone address generator 4 receives a signal synchronously with raster scan from a deflection circuit 20 and generates a zone address. Then a video signal generator 51 of a computer main body 50 generates a video signal for convergence correction and an input device 52 of the computer 50 is used to generate correction data, and a communication circuit for the communication between the computer main body 50 and the DDC device in the CRT display device is provided to the DDC device.