The purpose of the present invention is to provide a novel triazine derivative of the formula (I):whereinR1 represents a substituted or unsubstituted lower alkyl group,R2 represents a hydrogen atom or a substituted or unsubstituted lower alkyl group,A represents a nitrogen atom or C—R3,R3 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, andR4 represents a substituted or unsubstituted lower alkyl group,or a substituted or unsubstituted cycloalkyl group,or a pharmaceutically acceptable salt thereof.
