PURPOSE: To produce a polyurea by using an inorganic carbonate at atmospheric pressure, by dispersing and dissolving the inorganic carbonate and a diamine together with a triarylphosphine in a solvent such as pyridine and reacting this solution with a halohydrocarbon.

CONSTITUTION: 1mol of an inorganic carbonate (A) (e.g., Li2CO3) and 1mol of a diamine (B) (e.g., 1,4-diaminobenzene) are dissolved in a solvent which can dissolve these materials and the formed polyurea, such as a basic heterocyclic compound (e.g., pyridine), so that the concentration of each compound may be 0.05W0.6mol/l. 1.8W2.3mol of a triarylphosphine (D) (e.g., triphenylphosphine) and, optionally, 1W3mol of a crown ether (E) such as 18-crown-6 are added to the solution and dissolved. About 1.8W2.3mol of a halohydrocarbon of the formula (wherein n is 1W3 and X's are Cl and/or Br) (except for hexachloroethane) is added to this solution, and the resulting mixture is reacted at 30W100°C for 1W40hr. After completion of the reaction, the reaction mixture is poured into a large volume of a methanol/acetone mixture (1:1 by weight) and the precipitated polymer is recovered by filtration.