Abstract: 1. An aromatic amino acid derivative represented by the formula (I) or its pharmacologically acceptable salt: wherein, R1 is a hydrogen atom or an amino-protecting group, R2 is a halogen atom or an alkyl, aralkyl or aryl group, R3 is {circle over (1)} a hydrogen atom, {circle over (2)} an aroylamino group, {circle over (3)} a phenyl group substituted with lower alkyl, phenyl, phenoxy, etc. {circle over (4)} a naphthyl or tetrahydronaphthyl group optionally substituted with hydroxy, lower alkoxy or di(lower)alkylamino, {circle over (5)} an unsaturated mono-cyclic heterocyclic group containing N, O and/or S substituted with lower alkyl, phenyl, naphthyl or tetrahydroquinolyl, {circle over (6)} an unsaturated or partially saturated condensed heterocyclic group containing N, O and/or S, optionally substituted with oxo, carboxy, amino, lower alkyl, etc.; X is a halogen atom, an alkyl group or an alkoxy group; Y is oxygen atom or nitrogen atom; I is 0 or 1; m is 0, 1 or 2; n is an integer of 0-5.