A fire extinguisher has a pipe member for containing a cylinder filled with liquefied extinguishing gas, and a pusher guide member and a nozzle having an ejection hole formed therein are fitted to upper and lower openings, respectively, of the pipe member. A cylinder receiver to which the cylinder is fitted is mounted to the pusher guide member, and a pusher having a needle provided with a striker pin is movably arranged within the pusher guide member. Axial movement of the pusher is inhibited by a safety plate fitted in a groove formed in the outer peripheral surface of the pusher. In the event a fire breaks out, after removing the safety plate, an extinguishing person strikes the pusher with the fire extinguisher aimed at the origin of the fire, whereupon the pusher moves together with the needle, while compressing a spring interposed between the pusher and the cylinder receiver, and the striker pin of the needle breaks a seal plate of the cylinder, whereby the fire-extinguishing gas in the cylinder fills in a passage defined between the cylinder and the pipe member via a passage formed in the striker pin, the needle and the cylinder receiver, and then ejected from the ejection hole toward the origin of the fire.