The present invention relates to a process for producing a substituted amine represented by the general formula (IV):R.sup.2 NHOR.sup.3 (IV)(wherein R.sup.2 represents a hydrogen atom, a hydrocarbon group or a heteroatom-containing hydrocarbon group, and R.sup.3 represents a hydrocarbon group or a heteroatom-containing hydrocarbon group), which comprises the steps of:(b) reacting a hydroxamic acid represented by the general formula (II):R.sup.1 CONHOH (II)(wherein R.sup.1 represents a hydrogen atom or a hydrocarbon group) in the presence of a base with a reaction reagent capable of introducing a hydrocarbon or a heteroatom-containing hydrocarbon group to an oxygen atom and/or a nitrogen atom to form a substituted hydroxamic acid represented by the general formula (III): ##STR1## (wherein R.sup.1, R.sup.2 and R.sup.3 possess the same meanings as defined above),(c) hydrolyzing said substituted hydroxamic acid (III) in the presence of a base or an acid to produce a substituted amine represented by the general formula (IV):R.sup.2 NHOR.sup.3 (IV)(wherein R.sup.2 and R.sup.3 possess the same meanings as defined above). The present further relates to a method for purifying a synthetic intermediate for said substituted amine.