An object of the present invention is to provide a heterocyclic compound or a salt thereof that controls a pest.The present invention provides a heterocyclic compound represented by Formula (1): or a salt thereof, wherein R1 and R4 are identical or different and each represents substituted or unsubstituted aryl, or a substituted or unsubstituted heteroaryl group, R2 represents substituted or unsubstituted C1-4 alkyl, R3 represents substituted or unsubstituted aryl or a substituted or unsubstituted heteroaryl group, X represents C(=Y), CR5R6, NH, or NR7, Y represents oxygen or sulfur, R5 and R6 are identical or different and each represents hydrogen, or the like, R7 represents C1-4 alkyl, C1-4 alkylcarbonyl, or C1-4 alkoxycarbonyl, and the bond represented by: is a single bond or a double bond.本發明之一目的係提供一種控制害蟲之雜環化合物或其鹽。本發明提供一種以化學式(I)表示之雜環化合物:或其鹽,其中,R1及R4係相同或不同,且每一者表示經取代或未經取代之芳基,或者一經取代或未經取代之雜芳基基團,R2表示經取代或未經取代之C1-4烷基,R3表示經取代或未經取代之芳基,或者一經取代或未經取代之雜芳基基團,X表示C(=Y)、CR5R6、NH,或NR7,Y表示氧或硫,R5及R6係相同或不同,且每一者表示氫等,R7表示C1-4烷基、C1-4烷基羰基,或C1-4烷氧基羰基,且以表示之鍵係一單鍵或一雙鍵。