To provide a multi-shaft type vehicle capable of changing left and right intermediate part cylinders over in a plurality of modes and with no trouble of generating cavitation, boost pressure, working nonconformity, etc.

This multi-shaft type vehicle is furnished with a steering control means 1 to control the left/right side cylinders to steer wheels of front part, intermediate part and rear part steering shafts, a first intermediate part change-over valve 4V1and a second intermediate part change-over valve 4V2at three positions to change the cylinders over in a first mode that hydraulic pressure of working oil works in a head side oil chamber and a rod side oil chamber of the left/right side intermediate part cylinders 4a, 4b by proper change-over, a second mode that the hydraulic pressure of the working oil works only in the head side oil chamber and a third mode that the hydraulic pressure of the working oil works only in the rod side oil chamber are provided in an intermediate part hydraulic circuit 4 to which a front part hydraulic circuit 2 and a rear part hydraulic circuit 3 are communicated through in series by change-over of a front part change-over valve 2V, and an oil return subsidiary line 5 to eliminate excessiveness and shortage of the working oil to reversibly move from one of the intermediate part cylinders to the other of them is provided.

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