Polyurethane foam is widely used in various fields, such as transport machine, building materials and clothing. Polyurethane foam is a thermosetting resin and then the recycling of polyurethane foam is difficult. As the useful utilization of waste polyurethane foam, we produced activated carbons having high specific surface area by the chemical activation with potassium carbonate from polyurethane foam. In this method, we physically mixed the pulverized polyurethane with potassium carbonate. We investigated the influence of the producing conditions on the pore structure of the produced activated carbon. The influence of the particle size of pulverized polyurethane foam on the specific surface area was very small. The specific surface area of the activated carbon was at a maximum value (about 3000 m2/g) at a carbonization temperature of 1073 K and at an impregnation ratio of 1.0. We examined the adsorption properties of various organic vapours on the produced activated carbon. The amount of organic vapours (such as benzene, acetone, and octane) adsorbed on the produced activated carbons was much larger than those on the traditional coconut shell activated carbon and the same as those on the commercial activated carbon with high specific surface area. We surmised that the high specific surface area was due to the modification of the carbonization behaviour of polyurethane foam by potassium carbonate.