To obtain an excellent filter effect by forming a many small filtering opening forming a filter at a part of the inner peripheral surface of a cylindrical coupling part to which a coupling hose feeding medium is coupled, in a hand piece for dental use, etc., with a spray duct guiding a spray medium.

The hand piece 1 is vertically provided with two delivery ducts at its head part to be respectively supplied with a necessary medium through the spray duct. An at least one (two in the figure) annular grooves 6 are formed at the inner peripheral surface of the coupling part 4 of the end part on the joint side of the hand piece 1 like this way and the many small filtering openings 7 are formed at the groove bottom of each grooves 6. After passing through these openings 7, the spray medium reaches an annular duct or a collecting duct 8 to be supplied for the spray duct through a suction cavity 9 in addition. At his time, passing-through opening 7... is operated as a filter at this time to remove foreign matters in the spray medium.