PURPOSE: To readily obtain the subject compound without using so much organic solvent in high yield by reacting allyl halide and secondary amine in water solvent in the presence of inorganic alkali and recycling waste water separated from reacted liquid into the reaction system.

CONSTITUTION: Allyl halide such as allyl chloride is reacted with secondary amine expressed by the formula (R1 and R2 are 1-4C alkyl) such as dimethylamine at 10-80°C for 2-10 hour and under pressure, in the presence of inorganic alkali such as NaOH and in water solvent and waste water separated from reacted liquid is concentrated, then separated alkali halide is removed, thus inorganic alkali is dissolved and supernatant liquid containing diallyldialkylammonium halide is recycled into the reaction system to afford the aimed compound such as allyl dimethylamine useful as intermediate of waste water-treating agent, paper strength resin or agricultural chemicals, etc. Said method is industrially advantageous because an amount of waste water is steeply reduced, waste water problem is lightened and cost of waste water is reduced.