The present invention provides a method capable of industrially producing a target product, i.e., a compound represented by the aforementioned formula (I) or a salt thereof, which is useful for preventing and treating cerebrovascular disorders such as cerebral infarction, cerebral hemorrhage, subarachnoid hemorrhage, and cerebral edema, particularly for preventing and treating glaucoma, at high yield even on a large scale without imposing a negative impact on the environment. The present invention provides a method for producing a compound represented by formula (I) or a salt thereof, wherein the method comprises a step of reacting a compound represented by formula (III) or a salt thereof with a compound represented by formula (II) in the presence of at least one solvent selected from the group consisting of a nitrile solvent, an amide solvent, a sulfoxide solvent, and a urea solvent, and a base.