The present invention provides a piperazine compound represented by Formula (I) or a salt thereof, wherein X represents CH or an N atom; R1 represents C1-6 alkyl; R2 represents C1-6 alkyl that may have one or more substituents, C2-6 alkenyl that may have one or more substituents, —(C═O)—N(R3)(R4), or —(C═O)—OR5, R3 and R4 are the same or different, and each represents hydrogen or C1-6 alkyl that may have one or more substituents; or R3 and R4, taken together with a nitrogen atom to which R3 and R4 are attached, may form a saturated heterocyclic group; and R5 represents hydrogen or C1-6 alkyl that may have one or more substituents or aralkyl.