Abstract: The present invention comprises a method of producing .beta.-1,3-glucan wherein a microbe capable of producing .beta.-1,3-glucan is cultured in a medium containing as a nitrogen source an ammonium salt of an organic carboxylic acid the microbe can assimilate wherein the .beta.-1,3-glucan is produced and accumulated, and then harvesting. The .beta.-1,3-glucan production method of the present invention does not require addition of a pH regulator such as calcium carbonate or alkali ions, since the medium does not decrease in pH because a microbe capable of producing .beta.-1,3-glucan is cultured in a medium containing as a nitrogen source an ammonium salt of an organic carboxylic acid which the microbe can assimilate. For this reason, cultivation is not adversely affected, nor does any salt form in the medium, aspects which facilitate purification of said glucan, offering an industrially excellent production method. Moreover, the method of the present invention makes it feasible to produce .beta.