Provided are a curable resin and a curable resin composition which have alkali-solubility and curability that can freely be adjusted and a high sensitivity, a liquid crystal panel substrate which can maintain an even cell gap, and a liquid crystal panel using the liquid crystal panel substrate to exhibit a superior display quality. A curable resin composition comprising an imide-containing copolymer having a molecular structure wherein a constitutional unit at least the following units are connected: a constitutional unit having a cyclic imide group represented by the formula (1), a constitutional unit having an acid functional group such as a carboxyl group; and a constitutional unit having a photopolymerizing functional group. In a liquid crystal panel substrate (color filter 103), plural spacers (column-shaped spacers 12) are disposed in a non-display region on a substrate 5.