A cellulose fiber-containing material comprising cellulose fibers having anionic groups, wherein the fiber width of the cellulose fibers is greater than 1000 nm, wherein the anionic group is at least one selected from a phosphoric acid group or a phosphoric acid group-derived substituent, a carboxy group or a carboxy group-derived substituent, and a sulfone group or a sulfone group-derived substituent, the amount of the anionic group is from 0.10 mmol/g to 5.2 mmol/g of the cellulose fibers, the yield of the cellulose fiber-containing material measured by the following measurement method is 50% by mass or more, the cellulose fiber-containing material has organic onium ions as counterions of the anionic groups, the organic onium ion is represented by the following formula: wherein in the formula, M represents a nitrogen atom or a phosphorus atom, and R 1 to R 4 each independently represent a hydrogen atom or an organic group, wherein at least one of R 1 to R 4 represents an organic group containing 5 or more carbon atoms, or that the total number of carbon atoms contained in R 1 to R 4 is 17 or more; the content of the organic onium ions is 1.0% by mass or more with respect to the total mass of the cellulose fiber-containing material, and the organic onium ions satisfy at least one condition selected from the following (a) and (b): (a) containing a hydrocarbon group having 5 or more carbon atoms; and (b) having a total carbon number of 17 or more, wherein the measurement method for the yield is the following: a cellulose fiber-containing material is immersed in ion exchange water for 24 hours, a solid concentration is adjusted to 20% by mass, and a dispersion treatment is carried out for 15 minutes using a high-speed rotating disperser at a circumferential speed of 10 m/s; and the obtained dispersed solution is subjected to wet classification on a JIS test sieve with an opening of 150 μm, and the yield is calculated according to the following equation: yield % by mass = absolute dry mass of cellulose fiber-containing material remain- ing in test sieve / absolute dry mass of cellulose fiber-containing material subjected to test × 100. the fiber width of the cellulose fibers is greater than 1000 nm, wherein the anionic group is at least one selected from a phosphoric acid group or a phosphoric acid group-derived substituent, a carboxy group or a carboxy group-derived substituent, and a sulfone group or a sulfone group-derived substituent, the amount of the anionic group is from 0.10 mmol/g to 5.2 mmol/g of the cellulose fibers, the yield of the cellulose fiber-containing material measured by the following measurement method is 50% by mass or more, the cellulose fiber-containing material has organic onium ions as counterions of the anionic groups, the organic onium ion is represented by the following formula: wherein in the formula, M represents a nitrogen atom or a phosphorus atom, and R 1 to R 4 each independently represent a hydrogen atom or an organic group, wherein at least one of R 1 to R 4 represents an organic group containing 5 or more carbon atoms, or that the total number of carbon atoms contained in R 1 to R 4 is 17 or more; the content of the organic onium ions is 1.0% by mass or more with respect to the total mass of the cellulose fiber-containing material, and the organic onium ions satisfy at least one condition selected from the following (a) and (b): (a) containing a hydrocarbon group having 5 or more carbon atoms; and (b) having a total carbon number of 17 or more, (a) containing a hydrocarbon group having 5 or more carbon atoms; and (b) having a total carbon number of 17 or more, wherein the measurement method for the yield is the following: a cellulose fiber-containing material is immersed in ion exchange water for 24 hours, a solid concentration is adjusted to 20% by mass, and a dispersion treatment is carried out for 15 minutes using a high-speed rotating disperser at a circumferential speed of 10 m/s; and the obtained dispersed solution is subjected to wet classification on a JIS test sieve with an opening of 150 μm, and the yield is calculated according to the following equation: yield % by mass = absolute dry mass of cellulose fiber-containing material remain- ing in test sieve / absolute dry mass of cellulose fiber-containing material subjected to test × 100.