A substrate for use in an ink jet recording head includes a plurality of heat generating resistive members formed on the substrate, a wiring pattern formed to be electrically connected with the heat generating resistive members, and a protection film formed on the heat generating resistive members and the wiring pattern to protect them from ink, and then, a vertically turn-up wiring structure is formed with an insulation film formed on the substrate, and one side of the wiring connected with the heat generating resistive members is arranged immediately below the heat generating resistive members in a width and a length larger than that of heat generating resistive members with the insulation film between them. For this substrate, the heat generating resistive members and the wiring positioned immediately below them are formed by polysilicon having impurities in different densities. With the structure thus arranged, it becomes possible to form the vertically turn-up wiring structure for heat generating resistive members arranged at pitches in high density using polysilicon.