The present invention relates to a hydrazine derivative represented by the formula (I): ##STR1## (wherein each of Ar.sup.1 and Ar.sup.2 is a substituted or unsubstituted phenyl group, a substituted or unsubstituted heteroaryl group, or the like, R.sup.1 is an alkyl group or the like, and A is a divalent radical having --C.dbd.N--N-- or --CH--NH--N-- as a fundamental skeleton), which is a useful compound as an agricultural and horticultural insecticide.