To provide a bulldozer in which hydraulic pipes joined to hydraulic actuators mounted on a work machine frame pivotally supported between a vehicle body frame and a track frame from being damaged by sediment.

For example, both the hydraulic pipes including hydraulic hoses 66 and 68 for connecting an angle cylinder 52' to an operation valve 60 and the hydraulic pipes including hydraulic hoses 70 and 72 connecting a tilt cylinder 53 to the operation valve 60 are disposed in a route led from the inside of the vehicle body frame 2 to a corresponding hydraulic cylinder through a clearance between the vehicle body frame 2 and the work machine frame 5 and the inside of the work machine frame 5. A cover member 74' covering the hydraulic hoses 66, 68, 70, and 72 is installed between the vehicle body frame 2 and the work machine frame 5.