In a preferred embodiment of the present invention, a fuel tank is
supported by the front surface of an operator's cabin. A center frame
fixed to a body is coupled to the fuel tank via an external-force
transmission part. The external-force transmission part permits vertical
movement of the cabin relative to the center frame, while regulating
lateral movement of the cabin relative to the center frame when an
external force greater than a predetermined value is applied to the
cabin.