To produce the subject compound having excellent insecticidal activity against an insect belonging to the order Lepidoptera or Coleoptera at a low cost at high yield.

N,N'-diacyl-N'-t-alkylhydrazine compound expressed by the formula (R1 is a tertiary 4-8C alkyl; A and B are each independently phenyl or naphthyl), e.g. N'-t-butyl-N,N'-dibenzoylhydrazine. A compound of the formula is obtained by reacting a ketone or an aldehyde with N'-t-alkylhydrazine or its acid-added salt to form N-alkylidene-N'-t-alkylhydrazone, subsequently acylating the obtained hydrazone with an aromatic acid chloride to lead to N-alkylidene-N'-acyl-N'-t-alkylhydrazone, hydrolyzing the acylated hydrazone with a mild acid to obtain N'-acyl-N'-t-alkylhydrazine and further acylating the reaction product with an aromatic acid chloride. These reactions are preferably carried out at temperatures in the range from about 0°C to 90°C.