An insecticidal composition containing a guanidine derivative of the formula: wherein R is an optionally substituted homocyclic or heterocyclic group, n is 0 or 1, R is a hydrogen atom or an optionally substituted hydrocarbon group, R is a primary, secondary or tertiary amino group, X is an electron attractive group such as nitro or trifluoroacetyl group, provided that when n is 0, R is an optionally substituted heterocyclic group or a salt thereof.