To reduce the dimension of a power transmission device in a vehicle traveling direction in an all-landform traveling vehicle.

A crankshaft 13 with an oil pump 27 and a generating element 28 mounted on it is disposed between a primary shaft 40 and a secondary shaft 42 which a V-belt 48 is laid over. A balancer weight 36 is mounted to an auxiliary shaft 31. As the crankshaft 31 is disposed between the primary shaft 40 and the secondary shaft 42, a dead space created between the shafts can be effectively utilized, and, as a result, the dimension of a vehicle body in the vehicle traveling direction can be reduced. As the balancer weight 36 is mounted to the auxiliary shaft 31, there is no need to provide a balancer shaft and the dimension of the vehicle body in the vehicle traveling direction can be further reduced.