The purpose of the present invention is to provide a novel triazine derivative of the formula (I): wherein R 1 represents a substituted or unsubstituted lower alkyl group, R 2 represents a hydrogen atom or a substituted or unsubstituted lower alkyl group, A represents a nitrogen atom or C-R 3 , R 3 represents a hydrogen atom, a cyano group, a substituted or unsubstituted acyl group, a substituted or unsubstituted sulfonyl group, or a substituted or unsubstituted carbamoyl group, and R 4 represents a substituted or unsubstituted lower alkyl group, or a substituted or unsubstituted cycloalkyl group, or a pharmaceutically acceptable salt thereof.
