To provide a manufacturing method which can adjust the lengths of a recording element and a reproducing element for enabling manufacture of high-quality magnetic head sliders. The manufacturing method comprises: a stacked-layer forming step which stacks magnetic heads on a substrate; a lapping step which cuts out a bar block having a plurality of connected magnetic head sliders, and polishes a flying surface; and a slider cutting step which cuts out individual magnetic head sliders from the bar block. The stacked-layer forming step forms a reproducing-element polish amount detecting sensor on a same layer as that of the reproducing element, and forms a recording-element polish amount detecting sensor on a same layer as that of the recording element. The lapping step carries out polishing based on each output value of the reproducing-element polish amount detecting sensor and the recording-element polish amount detecting sensor.