A method of forming an image containing the step of: ejecting droplets of an ink-jet ink containing water, a colorant and a polymer through a nozzle of an ink-jet head onto an image recording medium, wherein the polymer has a hydrophilic main chain and a plurality of side chains which are capable of cross-linking between the side chains by irradiation with an active energy ray; and a shearing stress is continuously applied to the ink-jet ink in an ink-jet head channel of the ink-jet head during the time when the ink-jet head is in a stand-by condition to eject the droplets of the ink-jet ink.