Provided is a steering system comprising a priority pump (7) arranged between a hydraulic pump (2) and a steering valve (4) for performing a control to hold the longitudinal differential pressure of a meter-in oil passage of the steering valve (4) at a target value, so that the oil pressure discharged from the hydraulic pump (2) may be preferentially fed to steering cylinders (103a and 103b). Thesteering system further comprises a pressure sensor (31) for detecting the load pressures of the steering cylinders (103a and 103b), so that the target value to be set in the priority valve (7) is corrected by control means composed of a controller (32), an electromagnetic valve (33), a pilot oil passage (29) and a pressure receiving portion (24c) of the priority valve (7), on the basis of the load pressures detected by pressure detecting means. Thus, it is possible to suppress the shocks at the beginning of a turning motion of a steering wheel.