The invention provides a polishing liquid for polishing a barrier layer of a semiconductor integrated circuit, the polishing liquid comprising: a diquaternary ammonium cation; a corrosion inhibiting agent; and a colloidal silica, wherein the pH of the polishing liquid is in the range of 2.5 to 5.0. According to the invention, a polishing liquid capable of achieving a superior barrier layer polishing rate, as well as suppressing the occurrence of scratching due to the agglomeration of solid abrasive grains can be provided.