PURPOSE: To eliminate risk of the cutter revolving speed lowering in an arrangement pressure fluid is fed from the same hydraulic source to a hydraulic motor to drive a rotary cutter installed on a hydro-phrase excavating machine and a hydraulic cylinder for attitude controlling, even in case the hydraulic cylinder is in use, and to eliminate the energy loss in case that is used.

CONSTITUTION: A gear type flow divider 9 is connected with a hydraulic unit 5 as a hydraulic source, and the pressure fluid is sent divergently to a hydraulic motor 1 and a hydraulic cylinder 3 through this flow divider 9. In the case these motor 1 and cylinder 3 are out of service, the corresponding pressure fluid is bypassed by selector valves 15, 17.