A liquid discharge head which is inexpensive, accurate, and highly reliable, and a method of manufacturing such a liquid discharge head are provided. On a substrate, a thermal crosslinking positive photosensitive material layer (a first positive photosensitive material layer) and a second positive photosensitive material layer are formed. First a pattern is formed on the second positive photosensitive material layer, then another pattern is formed on the first positive photosensitive material layer. Next, a negative resin for forming a liquid channel wall is laminated on the patterned first and second positive photosensitive material layers. A discharge port is formed in the negative resin layer and then the positive photosensitive material layers are removed. At this time, the first positive photosensitive material layer is an ionizing radiation decompositive positive resist composed of a methacrylic copolymer composite mainly containing methacrylic acid where a metacrylic acid unit is 2 to 30 wt % and molecular weight is 5,000 to 50,000, and the second positive photosensitive material layer is an ionizing radiation decompositive positive resist mainly containing polymethyl isopropenyl ketone.