Abstract: An apparatus for evaporating ordinary temperature liquefied gases. The apparatus includes an ordinary temperature liquefied gas storing vessel, an evaporating chamber for evaporating a liquefied gas, and a liquid level detecting chamber for detecting the liquid level in the evaporating chamber. The detecting chamber is disposed between the storage vessel and the evaporating chamber. The liquid outlet from the storage vessel and detecting chamber are connected together by a conduit equipped with a liquid pressure reducing valve, the bottom of the detecting chamber and the liquid inlet to the evaporating chamber are connected together by a liquid conduit, and the respective gas outlets from the detecting chamber and evaporating chamber are connected to a gas warming chamber.