A liquid crystal-aligning agent comprising at least one of a polyamic acid obtained by reacting (A) a tetracarboxylic acid dianhydride consisting of 70 to 98 mole % of a dianhydride of a tetracarboxylic acid such as
or the like,
and 2 to 30 mole % of a dianhydride of a cyclobutanetetracarboxylic acid, and (B) a diamine compound, and a polymer obtained by imidizing the polyamic acid.