PROBLEM TO BE SOLVED: To provide a foamable composition for polyurethane foam which can impart effective mildew resistance to a polyurethane foam material produced by utilizing carbon dioxide as a foaming agent, while securing useful characteristics in dimension stability or heat-insulating properties.SOLUTION: In production of a polyurethane foam using carbon dioxide as a foaming agent, 3-iodo-2-propynylbutyl carbamate is dissolved into a high boiling point polar solvent, and included into the foamable composition.