To realize hydraulic rotation/feeding drive having high reliability and whose maintenance is easy by opening for a time interval which is proportiond to a required stroke of a driving mechanism where a proportional valve is operated with a hydraulic motor and controlling the supply of a pressure medium to respective hydraulic motors of a mill.

A sleeve 6 with which a tube 5 is encircled is rotationally driven through spur gear devices 2, 3, 4 with the hydraulic motor 1. The sleeve 6 is joined with a chuck 7 on which a clamping jaw 8 is mounted. The clamping jaw 8 is abutted on the surface of the tube 5, the tube 5 is fast held and torque by operation of the hydraulic motor 1 is tansmitted to the tube 5. In the case that a crank angle ist is larger than the initial value start, the proportional valve is opened for time T. The chuck 7 is rotated at a rotational speed ρwith the hydraulic motor 1 and a rotational angle ρist is generated. A value ΔT to be corrected to the time interval T for which the valve remains as it is opened is calculated in proportion to the difference between a desired rotational angle ρsoll and the actual rotational angle ρist.