The present invention provides a (meth)acrylic acid copolymer-containing composition which can sufficiently exhibit both stability at low temperatures and a calcium phosphate scale inhibition ability. The present invention relates to a (meth)acrylic acid copolymer-containing composition containing a (meth)acrylic acid copolymer including: a structural unit (a) derived from at least one selected from the group consisting of (meth)acrylic acid and salts thereof; and a structural unit (b) derived from a sulfonic acid monomer (B), the copolymer containing the structural unit (b) in a proportion of 5 to 90 mol% based on 100 mol% of all structural units, and having a weight average molecular weight of 4,500 to 18,000, the composition containing a sulfur-containing inorganic component not incorporated into the copolymer at a concentration of 6,000 ppm or lower in terms of sulfur atoms.