A carboxamide can be produced in a high yield by a method for producing a carboxamide, for example, represented by formula (4): (wherein R1 and R3 are as defined below), the method comprising a step of allowing a carboxylic acid ester represented by formula (1): (wherein R1 represents an optionally substituented C1-C20 hydrocarbon group or an optionally substituented C3-C20 heterocyclic group, and R2 represents an optionally substituented C1-C20 hydrocarbon group), an amine represented by formula (2): R3—NH2  (2) (wherein R3 represents a hydrogen atom or an optionally substituented C1-C20 hydrocarbon group), and a formamide compound represented by formula (3): (wherein R3 is as defined above) to react in the presence of a metal alkoxide.