The reduction in reliably of a liquid discharge head due to the dissolution of a protective layer is suppressed. A substrate for a liquid discharge head includes a base substrate, a heat-generating resistive layer placed on the base substrate, a pair of lines placed on the base substrate, and a protective layer covering the heat-generating resistive layer and the lines. The protective layer contains a material represented by the formula SixCyNx, where x+y+z=100, 30≦x≦59, y≧5, and z≧15 on an atomic percent basis.