PURPOSE: To provide a steam stripping method and apparatus capable of improving the product yield as well as energy efficiency without causing dew condensation.

CONSTITUTION: A heavy fraction is extracted from the column bottom of a steam stripper 11 and a light fraction is separated from the heavy fraction with a vacuum drier 31 and refluxed to the main body of the steam stripper through an assistant refluxing line 41 to lower the partial pressure of steam at the column top, lower the dew condensation temperature and prevent the dew condensation on the concentration stage 16, etc., near the column top.