A method for purifying 1,4-diaminobutane comprising the steps of: culturing a microorganism producing 1,4-diaminobutane in a medium while being provided with a nitrogen source to produce at least one of 1,4-diaminobutane carbonate and 1,4-diaminobutane bicarbonate; preparing a fermented broth or a concentrate thereof that comprises at least one of 1,4-diaminobutane carbonate and 1,4-diaminobutane bicarbonate; separating a third composition comprising at least one of 1,4-diaminobutane carbonate and 1,4-diaminobutane bicarbonate by distillation of the fermented broth or a concentrate thereof; and removing carbonate by fractional distillation from the at least one of 1,4-diaminobutane carbonate and 1,4-diaminobutane bicarbonate comprised in the third composition to recover 1,4-diaminobutane, wherein the distillation is performed at a vapor temperature in a range of 30°C to 158°C and a pressure in a range of 1333 Pa (10 mmHg) to 101325 Pa (760 mmHg), wherein the fermented broth or a concentrate thereof is prepared without adding additional base material into a fermented broth or a concentrate thereof, wherein the nitrogen source is at least one selected from ammonia, an ammonium salt of an organic compound, a nitrogen-containing organic compound, ammonium bicarbonate, and ammonium carbonate, and the nitrogen source prevents generation of additional by-products besides a carbonate salt of 1,4-diaminobutane. culturing a microorganism producing 1,4-diaminobutane in a medium while being provided with a nitrogen source to produce at least one of 1,4-diaminobutane carbonate and 1,4-diaminobutane bicarbonate; preparing a fermented broth or a concentrate thereof that comprises at least one of 1,4-diaminobutane carbonate and 1,4-diaminobutane bicarbonate; separating a third composition comprising at least one of 1,4-diaminobutane carbonate and 1,4-diaminobutane bicarbonate by distillation of the fermented broth or a concentrate thereof; and removing carbonate by fractional distillation from the at least one of 1,4-diaminobutane carbonate and 1,4-diaminobutane bicarbonate comprised in the third composition to recover 1,4-diaminobutane, wherein the distillation is performed at a vapor temperature in a range of 30°C to 158°C and a pressure in a range of 1333 Pa (10 mmHg) to 101325 Pa (760 mmHg), wherein the fermented broth or a concentrate thereof is prepared without adding additional base material into a fermented broth or a concentrate thereof, wherein the nitrogen source is at least one selected from ammonia, an ammonium salt of an organic compound, a nitrogen-containing organic compound, ammonium bicarbonate, and ammonium carbonate, and the nitrogen source prevents generation of additional by-products besides a carbonate salt of 1,4-diaminobutane. wherein the distillation is performed at a vapor temperature in a range of 30°C to 158°C and a pressure in a range of 1333 Pa (10 mmHg) to 101325 Pa (760 mmHg), wherein the fermented broth or a concentrate thereof is prepared without adding additional base material into a fermented broth or a concentrate thereof, wherein the nitrogen source is at least one selected from ammonia, an ammonium salt of an organic compound, a nitrogen-containing organic compound, ammonium bicarbonate, and ammonium carbonate, and the nitrogen source prevents generation of additional by-products besides a carbonate salt of 1,4-diaminobutane. <EOS>