To provide a novel 2,6-diaminopyrimidine derivative by the following formula (I): A 2,6-diaminopyrimidine derivative is represented by the formula (I): wherein R 1 represents a substituted or unsubstituted lower alkyl group, or a substituted or unsubstituted alkoxy group, Ar represents a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, Z 1 and Z 2 represent carbon atoms, or either 1 or 2 of the Z 1 and Z 2 represent nitrogen atoms, Q is selected from a structure (a) or (b) described below: R 2 represents a substituted or unsubstituted lower alkyl group, or a substituted or unsubstituted cycloalkyl group, R 3 represents a hydrogen atom or a halogen atom, Y represents a nitrogen atom or a carbon atom, and the bond drawn with a dotted line parallel to a solid line on structure (a) represents either double bond or single bond.
