To provide a method for stabilization by which the discoloration and deterioration of purity of an isocyanate compound can simultaneously be suppressed and the quality can be kept for a long time and to obtain a stabilized isocyanate composition.

One or more kinds of compounds selected from 2- mercaptomethylbenzimidazole, 2,4-morpholinylthiobenzothiazole, tetraethylthiuram disulfide, zinc dimethyldithiocarbamate and tetrabutylthiuram disulfide are added to an isocyanate compound.