To obtain a polyisocyanate composition excellent in reactivity at low temperature, also good in preservation stability and useful as a raw material for various kinds of polyurethanes by including a specific diisocyanate and a specified polydiisocyanate.

The objective composition is obtained by allowing the composition to contain a diisocyanate of formula I [one or both of R1 and R2 are each formula II (k is 0-2; j and m are each 1-5; h is 0-2) with the proviso that when one of them is formula II, the other is a 2-12C alkylene], and a polyisocyanate having a skeleton of formula II regulated so that the content of the compound of the formula I in which n is 0 may be 30-90 wt.%, the content of the one of the formula I in which n is 1 may be 9.5-40 wt.%, and the content of the one of the formula I in which n is 2-4 may be 0.5-30 wt.%. The composition is produced, fop example, by reacting a polycyclic aliphatic diisocyanate of formula III with carbon dioxide gas in the presence of 0.001-10.0 wt.% alkyl group-containing tertiary phosphine based on the amount of the diisocyanate at (-20°C) to 80°C.