[en] A photocathode RF-Gun was installed as a high quality electron source at JAERI-Kansai-APR for laser wakefield acceleration experiment. A charge of 730 pC was produced by a frequency quadrupled Nd:YLF laser whose energy was 60 μJ on a copper cathode surface. A photo-emitted charge increased as the RF-power increased. This enhancement of charge is known as Schottky effect. Quantum efficiency (QE) and a field emission dark current were measured during RF-conditioning. QE and the dark current were reduced with the progress of RF-conditioning after a leak of SF₆ gas. In order to reduce the dark current, the RF-conditioning is been continuing. (author)