A monolithic ink-jet printhead includes a substrate having an ink chamber to be filled with ink to be ejected on a front surface, a manifold for supplying ink to the ink chamber on a rear surface, and an ink channel communicating between the ink chamber and the manifold, a barrier wall formed on the front surface of the substrate to a predetermined depth and defining at least a portion of the ink chamber in a width-wise direction, a nozzle plate including a plurality of material layers stacked on the substrate and having a nozzle penetrating the nozzle plate, so that ink ejected from the ink chamber is ejected through the nozzle, a heater formed between adjacent material layers and located above the ink chamber for heating ink to be supplied within the ink chamber; and a conductor for providing current across the heater being provided between adjacent material layers.