Provided are a binder aqueous solution for a lithium-ion battery, a slurry for a lithium-ion battery negative electrode, a negative electrode for a lithium-ion battery, and a lithium-ion battery. The binder aqueous solution for a lithium-ion battery contains a water-soluble poly(meth)acrylamide (A). The water-soluble poly(meth)acrylamide (A) is a polymer of a monomer group containing, with respect to 100 mol % of the monomer group, 30 mol % to 95 mol % of a (meth)acrylamide group-containing compound (a), and 5 mol % to 40 mol % of an alkoxyalkyl (meth)acrylate (b) represented by the following general formula (1), CH2═C(R1)—CO—O—R2—O—R3  (1) (in which R1 is a hydrogen atom or a methyl group, R2 is an alkylene group having 1 to 4 carbon atoms, R3 is an alkyl group having 1 to 4 carbon atoms, and a total number of carbon atoms of the groups R1, R2 and R3 is 5 or less.)