A method is for manufacturing cellulose microfibers in which a problem of yellowing of cellulose microfibers to be obtained was solved, and cellulose microfibers.
As to a method for manufacturing cellulose microfibers, cellulose fibers are added with an additive (A) consisting of at least one of a phosphorous acid and a metal phosphite and an additive (B) consisting of at least one of urea and a urea derivative, heated and washed, then fibrillated. Also, as to cellulose microfibers, the fiber width is 1 to 1000 nm, and a part of hydroxy groups of cellulose fibers is substituted with a functional group represented by a predetermined structural formula to introduce an ester of phosphorous acid.