The present invention relates to a 1,2,4-thiadiazole compound of the formula (I) represented by the formula (1): wherein R1? represents C3-C7 alkynyl and 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?, ethylene-oxy-ethylene optionally substituted with one to four of R4?, or ethylene-thio-ethylene 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 pests controlling activity, and can effectively control an pests such as insect pests, acarine pests and the like ##STR00001##