The invention provides an aqueous ink containing a coloring material, wherein the coloring material is a self-dispersible pigment in which a functional group containing another atomic group and an anionic group such as a carboxylic acid group, a sulfonic acid group, a phosphoric acid group or a phosphonic acid group are bonded to a particle surface of a pigment such as carbon black or an organic pigment, and a standard deviation of an introduced amount of the functional group is 0.0380 or less.