To provide a gas filling vehicle capable of filling gas through a general low- or medium-speed gas conduit without necessarily requiring facilities for quick filling stations and of improving the utilization factor of gas by stably supplying prescribed pressure gas from filling cylinders, regardless of internal pressure on a filled side without causing a great increase in cost and weight.

The gas filling vehicle 1 which travels with, at least, a gas engine (travel driving source) 14, a transmission (travel driving system) 15 and filling cylinders 12A, 12B 13A-13C for filling gas into other places, mounted thereon, comprises a filling machine 16 mounted thereon the be driven by a gas engine 14 for filling gas through an external gas conduit into the filling cylinders 12A, 12B, 13A-13C via the filling machine 16.