Abstract: The present invention provides an inkjet ink which is excellent in image quality and high-speed printing on plain paper, in storage stability and in ejection stability and gives less load on a maintenance device for an inkjet recording apparatus; and an ink cartridge, an inkjet recording apparatus, and an inkjet recording method, using the inkjet ink. An inkjet ink containing a water dispersion of pigment-containing water-insoluble vinyl polymer particles; a water-soluble organic solvent; and water, wherein an ink residue from the inkjet ink has a viscosity of 3,000 mPa·s or less, the ink residue is obtained by leaving the inkjet ink to stand at a temperature of 25° C. and a humidity of 15% until substantially no mass change occurs, and wherein the inkjet ink, pH of which is adjusted to 7 with an acid, has a viscosity of 500 mPa·s or more.