Provided is a method for producing a 2-alkylcarbonylnaphtho[2,3-b]furan-4,9-dione-related substance, which is suitable for the production on an industrial scale. The present invention provides: a method for producing an intermediate for the production of a 2-alkylcarbonyl[2,3-b]furan-4,9-dione, which comprises reacting a 1-butyne derivative in which a ketone or an alcohol is protected with a 2-hydroxy-1,4-naphthoquinone derivative having a leaving group at position-3 in a solvent in the presence of a metal or a metal compound and a base; and a substance relating to the intermediate.