The purpose of the present invention is to provide a mesoionic compound or a salt thereof that exhibits excellent control activity against various pests. Provided is a mesoionic compound represented by formula (1).(In the formula, Ra represents a hydrogen atom or a methyl group, R1 represents a phenyl group or pyridyl group which is optionally substituted with up to two substituents selected independently from R2, and R2 represents a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a c-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a methyloxy group, an ethyloxy group, an n-propyloxy group, an i-propyloxy group, a c-propyloxy group, an n-butyloxy group, an i-butyloxy group, a s-butyloxy group, a t-butyloxy group, an n-pentyloxy group, a trifluoromethyloxy group, a 2,2,2-trifluoroethyloxy group, a methylthio group, a methylsulfoxy group, a methylsulfonyl group, a vinyl group, an ethynyl group, etc.)
