We have been developing CNT emitter to aim a high current density of a couple of 100A/cm² and a high total current up to 100mA. A current density over 300 A/cm² at 9.6MV/m and a total current of 15 mA was already achieved in a continuous DC mode. Such a high current density is attributed to so called rooting technique of CNT into the substrate. In order to increase a total emission current keeping a high current density and to avoid emittance growth, fabrication of a field emitter array with a gate was tried. The fabricated FEA was tested at an electron gun test stand in PSI and its preliminary beam characteristics were measured.