To provide a novel triazine derivative represented by the following formula (I):A triazine derivative represented by the following formula (I) :whereinR1 represents a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic ring, a substituted or unsubstituted heterocyclic fused ring, or a substituted or unsubstituted alkynyl group,R2 represents a hydrogen atom, a halogen atom, a substituted or unsubstituted lower alkyl group, or a substituted or unsubstituted alkoxy group,R3 represents a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic ring, or a substituted or unsubstituted heterocyclic fused ring,R4 represents a hydrogen atom, a substituted or unsubstituted lower alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, or a halogen atom, andR5 represents a hydrogen atom, a substituted or unsubstituted lower alkyl group, or R1 and R5 may be combined to form a saturated or unsaturated 5- to 6-membered ring, thereby forming a multiply fused ring,or a pharmaceutically acceptable salt thereof.
