To correct middle pin cushion distortion, in addition to correction of lateral mis-convergence of corners of a screen.

This correction device has a 1st saturable reactor 11, including two coils L1, L2 receiving a fixed bias magnetic field and a 2nd saturable reactor 16, including two coils L5, L6 receiving a bias magnetic field in response to a vertical deflection current and is configured to combine parabolic currents with a horizontal period flowing to two convergence correction coils L8, L9 which are connected to each output terminal in response to each inductance of balance coils L10, L11 to simultaneously correct corner lateral mis- convergence, X-axis lateral mis-convergence and middle, left/right pin distortions.