PURPOSE: To prevent the magnetic field of a deflection coil from being disturbed by a magnetic shield case in a CRT indicator.

CONSTITUTION: A substantially T-shaped correcting magnetic plate 2 consisting of a ferromagnetic body such as permalloy is vertically provided on the phosphor screen 3a side opening part of the CRT 3 of a deflection coil body1. When a current is carried to the deflection coil body 1, a magnetic filed is generated in the deflection coil, and the magnetic flux is partially leaked to the outside of the deflection coil body 1. The leaked magnetic flux passes the outer circumferential part of the deflection coil through the correcting magnetic plate 2, and is never attracted by a shield case 4. Thus, a normal magnetic field is formed near the deflection coil, and no unnecessary magnetic field is formed in the shield case 4. The screen movement or convergence error of the CRT is never caused.