We prepared SiNx film by pulsed laser ablation from Si target and nitrogen gas. We found that control of gas pressure is important to prepare stable and near stoichiometric film. The nitrogen content in the film increased with increasing nitrogen pressure up to 10 Pa. On the other hand, the film prepared at above 15 Pa easily oxidized in the atmosphere. The nitrogen molecule was decomposed to radicals by plume and reactions between Si and nitrogen take place up to 10 Pa. At higher pressure, formation of SiNx cluster in the plume prevent the production of high quality SiNx film.