Abstract: The present invention provides a method for removing nitrate from a solution comprising a salt component, wherein the method transplants sulfur bacteria to a sulfur-containing plant, and enables the sulfur-containing plant to which the sulfur bacteria is transplanted to contact a solution that comprises a salt component so as to remove nitrate from the solution comprising the salt component. The present invention also provides a solution comprising the salt component prepared by the method, and provides a salt comprising nitrate of 1.7 mg or lower per 100 g of salt.