A method of cathode heating using a laser was studied for an electron gun. In order to observe the practicality of the heating system, the characteristics of the laser‐heated gun with a dispenser and LaB6thermionic cathodes have been experimentally investigated. The direct laser irradiation is so efficient that the gun is equipped without heat shielding, a cooling system, or an electrical circuit in the gun chamber for cathode heating. Modeling, based on the experimental data, indicates that the cathode temperature is proportional to one‐fourth power of the laser power and that laser power loss and conduction loss of heat in the gun assembly are negligible. An electron beam current density 0.48 A/cm2was measured with 26 W laser power for a dispenser cathode of 0.06 cm2emission area. Current density 0.16 A/cm2with 25 W was recorded for a LaB6cathode of area 0.12 cm2. Electron beam emittance has been measured by using the typical pepper‐pot technique. It was observed that the growth of electron beam emittance was very small in the laser heating. ©1996 American Institute of Physics.