The present invention provides a method for producing cyclic chlorophosphazene oligomers, in particular the trimer and tetramer, in a high yield and selectivity. The method for producing cyclic chlorophosphazene oligomers involves the reaction between chlorinated phosphorus and ammonium chloride in the presence of a reaction catalyst, wherein 1) moisture is present in the reaction system at a molar fraction of 5.times.10.sup.-3 or less based on the total moles of the chlorinated phosphorus added to the reaction system, and 2) the ammonium chloride has an average particle size of 10 .mu.m or less and the value of particle size distribution of 2 or more, estimated by the Rosin-Rammler equation.