[Problem] The present invention provides a turbine rotation speed control system for a dental turbine handpiece, whereby the speed of a turbine blade can be controlled even when load variation occurs during a cutting operation, and good cutting characteristics with respect to an affected area can be realized. [Solution] The present invention is a turbine rotation speed control system 1 for a dental turbine handpiece 18a in which a turbine blade 19 provided in a turbine chamber is driven in rotation by compressed air supplied from an air source 31 via an external air supply pipeline and passed through an air supply pipeline inside a turbine handpiece body, and the compressed air is discharged as exhaust air from an exhaust pipeline, wherein the turbine rotation speed control system 1 for a dental turbine handpiece 18a has: an exhaust air variation detection means 61 provided with a speed detection unit 63 and a turbine blade 62 for exhaust air variation detection, for detecting variation in exhaust air that is discharged from the exhaust pipeline and flows through an external exhaust pipeline 52a； and an air flow rate adjustment means 71 provided with a proportional solenoid valve 81 and a feedback control circuit 72 for adjusting the inflow rate to the air supply pipeline of the dental turbine handpiece 18a in response to variation of the exhaust air and performing control so as to suppress variation in the speed of the turbine blade 19.Le problème abordé par la présente invention est de pourvoir à un système de régulation de vitesse de rotation d'une pièce à main dentaire de type turbine, de façon que la vitesse d'une aube de turbine puisse être régulée même quand une variation de charge se produit lors d'une opération de coupe, et que de bonnes caractéristiques de coupe d'une zone affectée puissent être obtenues. La solution selon l'invention concerne un système de régulation de vitesse de rotation de turbine 1 pour pièce à main dentaire de type turbine 18a, où un
