A cathode ray tube (CRT) has an electron gun including a cathode for emitting electron beams, a control electrode for controlling emission of the electron beams from the cathode, and a screen electrode for accelerating the flow of the electron beams passing the control electrode are arranged in series. In the CRT, during a scanning period, a voltage applied to at least one of the control electrode and the screen electrode changes in response to a voltage of a data signal applied to the cathode. The control electrode and screen electrode each include three mutually electrically insulated sections for independently controlling each of three electron beams passing through the electrodes.