The invention relates to a method for at least partially decolorizing sugar juice containing coloring substances. According to the inventive method, a sufficient amount of ozone is added to the sugar juice for the sugar juice to become at least partially decolorized. The ozone is made to react with at least one part of the coloring substances, whereby said sugar juice becomes at least partially decolorized. The amount of ozone added to the sugar juice corresponds to 50-400 ppm of the total amount of sugar contained in the sugar juice.
