Abstract: A ring magnetic sub-core having a plurality of protrusions inside is disposed adjacent to an electron gun side of a main magnetic core on which a horizontal deflection coil and a vertical deflection coil are wound, and an auxiliary vertical deflection coil connected with said vertical deflection coil is wound around said magnetic sub-core, thereby making it possible to have both improvement of convergence performance and reduction of barrel distortion be consistent with each other. Further, a convergence coil is wound around said magnetic sub-core so as to correct a transverse raster or a longitudinal raster.