There are provided a process, an apparatus, and an acrolein-containing composition, for producing acrylic acid from the acrolein-containing composition at a high yield. The process for producing acrylic acid includes a refinement step of removing phenol and/or 1-hydroxyacetone from an acrolein-containing composition and an oxidation step of oxidizing acrolein in the acrolein-containing composition after the refinement step to produce acrylic acid, and the apparatus to be used in the process includes a refiner to be used in the refinement step and an oxidation reactor for oxidizing acrolein to produce acrylic acid. The acrolein-containing composition is a composition having a (mass of phenol)/(mass of acrolein) ratio of 0.020 or lower and a (mass of 1-hydroxyacetone)/(mass of acrolein) ratio of 0.020 or lower.