Provided is a method for industrially and efficiently producing acetic acid having a good potassium permanganate test value without requiring a high cost. The method for producing acetic acid according to the present invention comprises: a carbonylation reaction step; a separation step; a recirculation process; a liquid separation process; and a separation step for separating the liquid on the basis of the liquid temperature at the time of separation in the separation step, the acetaldehyde concentration of the aqueous phase and/or the organic phase, the acetaldehyde fraction, the methyl acetate concentration of the aqueous phase and/or the organic phase, or the methyl acetate fraction. An acetaldehyde separation/removal step for selecting and treating an object to be treated from among atleast a part of the aqueous phase and/or the organic phase, the acetaldehyde separation/removal step being characterized in that the crotonaldehyde concentration in the first acetic acid stream is controlled to 2.2 ppm by mass or less and the crotonaldehyde concentration CCR (ppm by mass) and 2-acetic acid concentration in the first acetic acid stream are controlled to 2.2 ppm by mass or less; the ratio (CCR/CECR) of the ethyl crotonaldehyde concentration CECR (mass ppm) is adjusted.