An ammine solution which can be provided at low production cost, as compared with conventional ones. The ammine solution contains an ammine compound which contains at least one of platinum and palladium, and at least one kind of amine compound. By using the amine compound of which the boiling point is raised, as compared with that of ammonia, due to the substitution of substitution radicals for some of hydrogens in ammonia molecules, the volatilizing speed from the ammine solution can be restrained.