A hand piece includes a main body, an impeller, an air supplier, an exhauster and an exhaust controller. The impeller is received by the main body and is rotated in the main body. The air supplier is disposed at the main body and supplies an air to the impeller. The exhauster is disposed at the main body and exhausts the air supplied to the impeller. The exhaust controller is inserted into the exhauster and controls the exhaust of the air based on an air pressure exhausted from the exhauster.
