The unsaturated isocyanate compounds having in the molecule at least one free isocyanate group and at least one polymerizable unsaturated group can be prepared by the reactions expressed by the following formulae: ##EQU4## wherein R1 stands for a hydrogen atom, a methyl group or a group --COOR9 in which R9 is an alkyl group having 1 to 18 carbon atoms; R2 stands for a group ##EQU5## R3 and R4 stan