PURPOSE: To improve working efficiency and reliability and to effect a work to continuously hone an upper and an under surface by providing an injection nozzle which is horizontally and vertically revolable.

CONSTITUTION: In the case of a honing pattern in which honing is effected, in order, on an outer wall surface 11, a nozzle surface 10, and an inner wall surface 12, an arm is extended to a nozzle exchange device 4 at each step and a suitable injection nozzle 5 is selected and automatically exchanged. The arm is extended to a work to effect a honing work on the surface thereof. Upon completion of a work to hone the upper surface, the injection nozzle 5 is turned in a 180° arc and set in an up state. With this state, a honing work is continuously applied on the under surface.