The present invention relates to a liquid crystal aligning agent which contains at least one selected from the group consisting of a polysiloxane having a structure represented by the following formula (S-0) and synthesized through the step of hydrolyzing or hydrolyzing/condensing a silane compound in the presence of an alkali metal compound or an organic base, a hydrolysate thereof and a condensate of the hydrolysate: (in the above formula (S-0), R is a group having an alkyl group with 4 to 20 carbon atoms, a fluoroalkyl group with 1 to 20 carbon atoms or a cyclohexyl group, or a group having 17 to 51 carbon atoms and a steroid skeleton, and YI is a hydroxyl group, an alkoxyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms).