Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element

The present invention provides: a liquid crystal alignment film which has good liquid crystal alignment properties, while having excellent pretilt angle developability; a liquid crystal display element which is provided with this liquid crystal alignment film; and a liquid crystal aligning agent which enables the achievement of this liquid crystal alignment film. The present invention provides a liquid crystal aligning agent which contains: as a component (A), a compound that has a thermally crosslinkable group and a photo-alignment group represented by formula (pa-1), wherein the thermally crosslinkable group is capable of forming a covalent bond by being reacted with a carboxy group; and as a component (B), a polyamic acid and a solvent. (In formula (pa-1), A represents a phenylene group or the like; R1 represents —COO— or —OCO—; R2 represents a cyclohexane-1,4-diyl group; R3 represents a cyclohexane-1,4-diyl group; R4 represents a linear or branched alkyl group having 1 to 40 carbon atoms, and some or all of the hydrogen atoms in this alkyl group may be substituted by fluorine atoms; D represents an oxygen atom, a sulfur atom or —NRd-; a represents an integer of 0 to 3; and * denotes a bonding position.)