To facilitate climbing over an obstacle by itself by extending a second elevating means while shrinking a first elevating means so as to elevate a vehicle body and extending/shrinking extension means in the rear part and in the front part while extending the second elevating means so as to move the vehicle body forward/ backward in a lifted condition.

While the first elevating means 12 are shrunk, an under carriage 10 is lifted by means of the second elevating means 14 on the right sides and the left sides in the front part and in the rear part. While the under carriage 10 is kept lifted, extension means 13 on the left side and on the right side in the front part are shrunk, and at the same time, extension means 13 on the left side and on the right side in the rear part are extended synchronously with this shrinking action, so that the vehicle body 10 is advanced, and a vehicle body 11 and the first elevating means 12 positioned on the left side and on the right side in the rear part of the vehicle body 11 are positioned in front of an obstacle 4. After the first elevating means 12 are extended so as to be landed while the second elevating means 14 are shrunk, the extension means 13 on the left side and on the right side in the rear part are shrunk, and subsequently, the first elevating means 12 is shrunk, so that the vehicle body 10 is landed. In this way, the vehicle can climb over the obstacle by itself and is moved easily.