PROBLEM TO BE SOLVED: To provide a method for producing a fish soy sauce that has a thin color tone and has a good taste and aroma.SOLUTION: Provided is a method for producing fish soy sauce, characterized by irradiating, in a fishery-product fermentation and maturation step of the fish soy sauce production process, an ultraviolet ray in a UV-A region or a visible ray in a blue region to the fishery-product.SELECTED DRAWING: NoneCOPYRIGHT: (C)2016,JPO&INPIT