The present invention addresses the problem of providing an industrial production method for a nitrogen-containing heterocyclic compound that has an excellent FLT3-inhibiting activity and is useful as an active pharmaceutical ingredient of a pharmaceutical agent. Provided is a production method using a compound represented by general formula [14] (in the formula, R1 represents an optionally substituted C1-6alkyl group, and R8 represents a leaving group or the like) or a salt of said compound.
