The invention provides an aqueous ink containing a self-dispersible pigment having a carboxylic acid group bonded directly or through another atomic group to a particle surface of a pigment and a lactone group bonded to the particle surface of the pigment, wherein, as determined by a selective neutralization method, an introduced amount of the carboxylic acid group is 0.60 mmol/g or more and a ratio of an introduced amount (mmol/g) of the lactone group to the introduced amount (mmol/g) of the carboxylic acid group is 0.20 time or less.