PURPOSE: To facilitate assembling and to ensure control operation, by controlling the related operation of steering brakes and a central clutch by providing one linking valve device.

CONSTITUTION: In the steering control apparatus 10, right and left transmissions 12a and 12b, the right and left steering brakes 16a and 16b, and the central clutch 20 are provided, and an oil hydraulic circuit for manipulating them by oil hydraulics is also provided. A pump 22 and a linking valve device 30 are provided in the oil hydraulic circuit. Said linking valve device 30 is provided with a brake control valve 31 which is operated by a brake pedal 24, and right and left steering control valves 33 and 32 which are operated by right and left steering levers, respectively. The linking valve device 30 controls the right and left steering brakes in a related manner with each other and the central clutch in accordance with the operations of the steering levers 26a and 26b or the brake pedal 24, respectively.