To provide a nozzle for a rotary gun which enables a widening of a treatment area coverage per unit time without leaving a moving trajectory of a water jet behind as a streak after spewing a water jet in sectoral shape on the surface to be treated, and also a shortening of working time.

The nozzle for the rotary gun includes a plurality of parallel jet nozzles 5 and 5 for spewing out a water jet in sectoral shape, which are formed at the apex surface of a nozzle body 1 for the rotary gun. In addition, the parallel jet nozzles 5 and 5 have an angle of inclination configured in the rotating direction to the rotating center axis, and are further arranged at a symmetric position to the center point.