Left and right brake pedals 35 and left and right brake mechanisms 563 are connected to and coordinated with each other by means of left and right brake link bodies 730, and brake cylinders 630 corresponding to the left and right brake link bodies 730 are connected thereto and coordinated therewith by means of cable members 731. First adaptable members 733 for preventing, when the brake mechanisms 563 are operated by the brake cylinders 630, the brake pedals 35 from operating following the operation of the brake mechanisms 563 are provided between the left and right brake link bodies 730 and the left and right brake pedals 35. Second adaptable members 736 for preventing, when the brake mechanisms 563 are operated by the brake pedals 35, the brake cylinders 630 from operating following the operation of the brake mechanisms 563 are provided between the left and right brake link bodies 730 and the left and right cable members 731.
