The present invention provides an in-plane-switching liquid crystal display element which exhibits excellent burn-in properties and efficiently controls orientation. To this end, the present invention provides a polymer composition containing: (A) a photosensitive side-chain polymer which exhibits liquid-crystal properties within a prescribed temperature range; (B) a cross-linking compound having, per molecule, two or more groups of at least one type of substituent group selected from a hydroxy group, a hydroxyalkyl group, an alkoxy group, an alkoxy-alkyl group, an oxirane group, an epoxy group, an isocyanate group, an oxetane group, a cyclocarbonate group, a trialkoxysilyl group, and a polymerizable unsaturated bond group; and (C) an organic solvent. Specifically, the present invention provides a method which makes it possible to produce a substrate having a liquid crystal orientation membrane, and to obtain a liquid crystal orientation membrane for use in an in-plane-switching liquid crystal display element having the ability to control orientation, by having the following steps: [I] a step for forming a film by applying said composition onto a substrate having a conductive film for in-plane switching; [II] a step for irradiating the film obtained in [I] with polarized ultraviolet rays; and [III] a step for heating the film obtained in [II].