The present invention provides a process for producing a substituted aniline compound represented by the following general formula (6): ##STR00001## (in the formula, R.sub.1, R.sub.2 and R.sub.3 are each independently an alkyl group, an alkoxy group, an alkoxyalkyl group, a haloalkyl group, a carboxyl group, an alkoxycarbonyl group, an alkyl-carboxamide group, a nitro group, an aryl group, an arylalkyl group, an aryloxy group, a halogen atom or a hydrogen atom; and X and Y are each independently a hydrogen atom, an alkyl group, an alkoxy group, an alkoxyalkyl group, a haloalkyl group, a carboxyl group, an alkoxycarbonyl group or a halogen atom), characterized by oxidizing a substituted indole compound represented by the following general formula (3): ##STR00002## (in the formula, R.sub.1, R.sub.2, R.sub.3, X and Y have the same definitions as given above) to give rise to the ring opening of indole ring to produce an acetanilide compound represented by the following general formula (4): ##STR00003## (in the formula, R.sub.1, R.sub.2, R.sub.3, X and Y have the same definitions as given above; and Ac is an acetyl group) and subjecting this compound to reduction and deacetylation, advantageously in industry.