An ink jet head substrate, an ink jet head and a method of manufacturing an ink jet head substrate are provided. The ink jet head substrate includes a substrate having an ink ejection region. An interlayer insulating layer is formed on the substrate. A plurality of pressure-generating elements that generate pressure to eject ink are disposed on the interlayer insulating layer to form a predetermined array. Segment heaters that heat the substrate are disposed at predetermined positions on the substrate. The segment heaters are electrically connected to each other by heater wirings.