Disclosed is a method for producing monofluoro methane, which involves at least a pyrolysis step in which a 1-methoxy-1,1,2,2-tetrafluoro ethane is pyrolyzed by bringing same into contact with a catalyst, and a step for collecting monofluoro methane from the pyrolysis product. As a consequence, it is possible to efficiently and practically produce monofluoro methane that essentially does not contain halogens except fluorine.