The present invention provides a high-purity acid-form sophorolipid (SL)-containing composition characterized by substantially not containing acetic acid. The high-purity acid-form SL-containing composition can be produced, for example, by the following method:(i) adjusting the pH of a partially purified acid-form SL-containing composition to an acidic range and(ii-a) subjecting an acidified partially purified acid-form SL-containing composition obtained in step (i) to chromatography to acquire a fraction containing an acid-form SL, or(ii-b) leaving the acidified partially purified acid-form SL-containing composition obtained in step (i) to stand under a low-temperature condition to acquire a resulting gelled object.
