Provided is a method for industrially efficiently producing acetic acid that yields a good potassium permanganate test result, without enormous cost. A light ends column (first distillation column) is operated with a reflux ratio at a specific level or more, a distillation column (crotonaldehyde-removing column) is provided for treating an organic phase of an overhead condensate from the light ends column, and the crotonaldehyde-removing column is operated under such conditions as to meet at least one of conditions (i) to (iii) as follows: (i) a reflux ratio at the distillation column is 0.01 or more; (ii) at the distillation column, the ratio of a crotonaldehyde concentration in a distillate to a crotonaldehyde concentration in a charge liquid is less than 1; and (iii) at the distillation column, the ratio of a crotonaldehyde concentration in bottoms to a crotonaldehyde concentration in the charge liquid is greater than 1.