Cellulose nanofiber dispersion liquid and method for producing same

Provided is a method for efficiently producing a highly transparent cellulose nanofiber with a small power consumption level. The present invention pertains to a method for producing a cellulose nanofiber dispersion liquid having an average fiber width of 3-100 nm, the method comprising: a preliminary fibrillation step (A) for beating a raw material pulp until the type-B viscosity of a pulp slurry containing the raw material pulp at a concentration of 3% (v/w) in water, serving as a dispersion medium, becomes 50 mPa·s or higher; and a true fibrillation step (B) for fibrillating the pulp obtained at the preliminary fibrillation step (A) until the fiber width becomes 3-100 nm.