Liquid crystal aligning agent, liquid crystal alignment membrane, liquid crystal display element, and method for manufacturing liquid crystal display element

Provided is a liquid crystal aligning agent comprising a constituent (A), a constituent (B), and a constituent (C), detailed below, as well as an organic solvent. Constituent (A) is at least one polymer chosen from the following: a polyimide precursor with a side chain that aligns liquid crystal vertically and a photoreactive side chain comprising at least one chosen from the group consisting of a methacryl group, an acryl group, a vinyl group, an allyl group, a coumarin group, a styryl group, and a cinnamoyl group; and a polyimide obtained through imidization of this polyimide precursor. Constituent (B) is a polymerizable compound with a photopolymerized or photocrosslinked group on at least one terminal. Constituent (C) is at least one polymer chosen from the following: a polyimide precursor obtained through the reaction of a tetracarboxylic dianhydride with a diamine with a photoreactive side chain comprising at least one chosen from the group consisting of a methacryl group, an acryl group, a vinyl group, an allyl group, a coumarin group, a styryl group, and a cinnamoyl group, and at least one diamine selected from the formulas (C-1)-(C-5) shown in the figure; and a polyimide obtained through imidization of this polyimide precursor. (In the formulas, Y 1 represents a secondary amine, a tertiary amine, or a monovalent organic group with a heterocyclic structure, while Y 2 represents a secondary amine, a tertiary amine, or a divalent organic group with a heterocyclic structure.)