In a process for producing a hydrogen-containing fluorinated hydrocarbon in which a halogenated hydrocarbon reaction raw material, which includes a chlorinated alkene and/or a hydrogen-containing chlorinated alkane, is subjected to a fluorination reaction with hydrogen fluoride in a liquid phase in a reactor in the presence of a fluorination catalyst to obtain a reaction mixture which includes the hydrogen-containing fluorinated hydrocarbon, the reactor to be used has a portion which is able to contact with the reaction mixture, at least a part of this portion being made of an alloy material of 18 to 20% by weight of chromium, 18 to 20% by weight of molybdenum, 1.5 to 2.2% by weight of at least one element selected from niobium and tantalum and the balance of nickel.