Abstract: The invention relates to a method for continually producing a suspension of cellulose in an aqueous tertiary amine oxide. The method includes (a) mixing cellulose and an amine oxide-free aqueous phase to form a cellulose suspension in a mass ratio in the range of 1:3 to 1:40, (b) dehydrating the cellulose suspension, wherein the dehydrated cellulose suspension has a cellulose content in the range of 20 to 80 percent-by-mass; (c) mixing the cellulose suspension with an aqueous amine oxide while the cellulose suspension is falling through a vertical fall zone to obtain an aqueous amine oxide-cellulose suspension with an amine oxide content in the range of 70 to 80 percent-by-mass; and (d) conveying the aqueous amine oxide-cellulose suspension through a horizontal shear zone. The invention also relates to a device for carrying out this method.