PURPOSE: To obtain a gasifier for using liquefied natural gas instead of liquefied petroleum gas as a carburant in the production of city gas through fractional distillation of a highly calorific component in liquefied natural gas by incorporating thereinto a plurality of specific constitutions. CONSTITUTION: The liquefied natural gas gasifier comprises an evaporator 10 for evaporating liquefied natural gas(LNG), a gas-liq. separator 4 for effecting gas-liq. separation of LNG evaporated from the evaporator 10, a heater 11 for heating the gas separated in the separator 4, pressure control means in the form of a pressure reducing valve 26 for pressure adjustment, which is capable of guiding gas while reducing the pressure thereof and is positioned downstream of the separator 4, pref. positioned between the separator 4 and the heater 11, and a vaporizer 5 for vaporizing a liq. obtd. by fractional distillation in the separator 4 as a carburant after mixing the lia. with LNG to be adjusted in calorific value.