Provided is an air turbine type dental handpiece capable of reducing a generated sound volume. An air turbine 2 is rotationally driven by compressed air that is supplied to the internal space of a housing 11, and the treatment such as cutting of the tooth of a patient is performed by a cutting tool 4. A blade 22 is a toroidal type blade (a blade having a shape in which a first blade portion 221 and a second blade portion 222 are continuous with each other at a bridge portion 224). Therefore, the generation of a large eddy current around the air turbine 2 is suppressed, and the generated sound volume is reduced.