To particularly apply an accumulator fixing device to a low floor type bus by extending a plate-like member for placing cylindrical accumulators along side frames between the left/right side frames, and integrating this plate- like member and the accumulators by a joining means.

In a pressure accumulating type hybrid vehicle 1 for receovring kinetic energy of the vehicle by accumulating high pressure oil in accumulators 4, 5, the two accumulators 4, 5 are arranged between left/right side frames 2, 3, and in this case, mounting rubber 6A, 7A, 6B, 7B of front/rear parts are suspended and held by the left/right side frames 2, 3 via bolts 8A, 9A, 8B, 9B, and a horizontal beam 10 composed of a plate-like member 12 having recessed parts 13, 14 on the upper side is extended between the respective mounting rubber 6A, 7A, 6B, 7B. After placing the accumulators 4, 5 on the respective recessed parts 13, 14, the accumulators 4, 5 are integrated into the plate-like member 12 by a joining means 19.