The invention is aimed at the sector of dental instruments, and in particular the invention relates to an improved disposable saliva ejector (1) for use in dentistry comprising a tube (2) made of plastic material, having a first end (3) connectable to a suction system of known type and a second free end (4) adapted to occupy the mouth of a patient, wherein said tube (2) comprises a plurality of corrugated portions (5, 6) and said ejector (1) comprises an arch (7) made of rigid plastic material adapted to cooperate with one of said corrugated portions (6) to give said ejector (1) a substantially U- shaped permanent bend.