from the deflecting coil 66 to voltage to thereafter output the same a control circuit 100 outputs a control signal reflecting a convergence distortion degree based on the voltage outputted from the temperature sensor 90 a correction data calculating circuit 110 calculates correction data based on the control signal and then outputs the same the correction data outputted from the correction data calculating means 110 is inputted into the convergence control unit 80 for control of the convergence coil 64 to then correct for convergence distortion based on the sensed temperature of the deflecting coil 66 the control circuit 100 has an analog to digital converter adc 102 for converting the voltage based on the temperature of the deflecting coil 66 outputted from the temperature sensor 90 to a digital signal a microcomputer 104 is also included for processing the digital signal and outputting a control signal representative of the convergence distortion degree for controlling the convergence the correction data calculating circuit 110 includes a convergence data storage unit 112 wherein convergence data is stored in advance such data represents data for controlling convergence accurately in a stable state of operation e g 25 degrees celsius a correction data storage unit 114 wherein the convergence data in accordance with a currently sensed temperature of the deflecting coil 66 is stored and an error operational unit 116 for calculating a difference of the convergence data outputted from the convergence data storage unit 112 and the convergence data outputted from the correction data storage unit 114 in accordance with the control signal outputted from the microcomputer 104 of the.