The stability of field emission current from B-doped diamond thin films terminated with hydrogen and oxygen mas measured to investigate the influence of the surface treatment and the dopant concentration on the emission stability. The diamond films sere prepared by microwave plasma chemical vapor deposition. The O-termination was performed by acid cleaning in boiling chromic acid and boiling aqua regia, The H-termination was performed by exposing the above sample to hydrogen plasma. The dependence of the emission stability on the B2H6 gas (dopant gas) concentration and the surface treatment Ras investigated. As a result, Little dependence on the B concentration nas observed, but dependence on the surface treatment was significant. The field emission of the H-terminated diamond thin films was confirmed to be more stable than the O-terminated films.