The present invention relates to a 1,2,4-thiadiazole compound of the formula (I):wherein R1 represents C3-C7 alkynyl X represents C4-C7 straight alkylene optionally substituted with one to four of R2, C4-C7 straight alkenylene optionally substituted with one to four of R2, or ethylene-thioethylene optionally substituted with one to four of R4 R2 represents a halogen atom, trifluoromethyl or C1-C4 alkyl and R4 represents a fluorine atom or C1-C3 alkyl. The 1,2,4-thiadiazole compound has an excellent pest controlling activity, and can effectively control pests such as insect pests, acarine pests and the like.
