Abstract: A hydraulic pipe arrangement of a working machine is not in contact with an obstacle and no torsion and no bending are generated. Accordingly, in a hydraulically driven type working machine provided with a boom (1) having a vertical swing supporting point supported at a base end side by a machine frame and a joint connection supporting point in a front end side, an arm (2) connected in a base end side to the joint connection supporting point, a boom driving hydraulic cylinder (6a) hoisting around a hoist supporting point provided in the machine frame so as to drive the boom, an arm driving hydraulic cylinder (7), and a working tool driving hydraulic cylinder (8), a swivel joint mechanism relaying a hydraulic pipe arrangement from a side of the machine frame is provided at a center of at least one of the vertical swing supporting point, the joint connection supporting point and the boom driving hydraulic cylinder hoist supporting point.