The present invention relates to an isothiocyanate production method using an organic primary amine and thiourea as starting materials; to a composition for transporting and storing an N-substituted O-substituted thiocarbamate that includes an N-substituted O-substituted thiocarbamate and a hydroxy compound, the equivalent weight ratio of hydroxy groups of the hydroxy compound with respect to the carbamate groups of the N-substituted O-substituted thiocarbamate being in the range of 1 to 100; to a composition for transporting and storing a compound with a thioureido group that includes a compound with a thioureido group and a hydroxy compound, the equivalent weight ratio of hydroxy groups of the hydroxy compound with respect to the thioureido groups of the compound with a thioureido group being in the range of 1 to 100; and to an isothiocyanate composition containing an isothiocyanate and a compound with a specific functional group.
