Novel 4-(3-butynyl)aminopyrimidine derivatives represented by general formula [I] are useful as pest control agents. In general formula [I], R 1 is a mono- or bi-cyclic ring which may contain 0 to 3 heteroatoms, for example, phenyl or oxazolyl； R 2 is a hydrogen atom, -R, -OR, -C(O)OR, -C(O)NHR, -CONR 2 (wherein R is straight-chain or branched C 1-8 alkyl, or the like), hydroxyalkyl, or the like； R 3 is a hydrogen atom, a halogen atom, acyloxy represented by (straight-chain or branched C 1-8 aliphatic hydrocarbon group) -CO-O-, or the like； and R 4 is a hydrogen atom, a halogen atom, C 1-6 alkyl, or the like, or alternatively, R 4 and R 3 together with the carbon atoms on the pyrimidine ring may form a thiophene ring, a pyrrole ring, an imidazole ring, a benzene ring, a pyrimidine ring, a furan ring, a pyrazine ring, or a pyrrolidine ring.
