A battery that supplies electric power to a battery-driven work vehicle, includes: battery cells; a casing including storing the battery cells in a space surrounded by the top, the bottom, and the sides thereof; an inlet hole open to the side to introduce a gas into the casing; an outlet hole open to a side facing the side to which the inlet hole is open, and discharging the gas from an inside of the casing; and a fan introducing the gas from the inlet hole into the casing to make the gas flow in contact with the top and bottom surfaces of the battery cells, and then discharging the gas from the inside the casing, wherein the casing includes rod-shaped members extended from the inlet hole to the outlet hole, and wherein the rod-shaped members come in contact with the bottom surface of the battery cell.