A cathode ray tube is provided having an electron gun equipped with a main lens having a function of controlling a shape of an electron beam spot which is deflected to the peripheral portion of a display screen, to improve a resolution at the peripheral portion of the screen of the cathode ray tube for use in a direct view color television receiver or a color display terminal. To reduce the dynamic correction voltage of the electron gun, an electrostatic quadrupole lens with a simple structure is used, thereby reducing deterioration due to the deflection aberration of the electron beam spot at the peripheral portion of the screen.