A deflection coil for deflecting an electron beam emitted from an electron
gun is provided outside a cathode-ray tube in which the electron gun is
housed, and a phosphor screen is formed. The cathode-ray tube further
includes a velocity modulation coil for modulating a horizontal scanning
velocity of an electron beam, a first magnetic substance surrounding an
outer circumference of the cathode-ray tube from outside the velocity
modulation coil, and a second magnetic substance surrounding the outer
circumference of the cathode-ray tube between the deflection coil and the
first magnetic substance. Because of this, the sensitivity of velocity
modulation can be enhanced effectively with a simple configuration while
deflection distortion is prevented.