PURPOSE: To reduce the whole size and a total weight of a propulsion drive system and an inclination drive system by assisting inclination of a clawler through inclination of a clawler and inversion propulsion movement.

CONSTITUTION: A vehicle body 202 pivotally mounts the swing arms 218 of four propulsion devices on a pivot 205. The swing arm 218 is provided with a drive sprocket 206 being an inclination drive means, an end part guide sprocket 207, a fist sprocket 222A, a central sprocket 210, and a propulsion drive motor 222, and propulsion and inclination movement are simultaneously effected. When an inclination clutch 234 is released, a clutch 214 is engaged, and a central sprocket 210 is locked, and when a motor 222 is run, reversion propulsion movement is generated through sprockets 222A and 206 togetherwith inclination movement through engagement between a first sprocket 222A and a fixed central sprocket 210. This constitution forms a vehicle in a compact manner and reduces its weight.