NOVELTY - Female sex hormone degrading bacteria belonging to Novosphingobium, Sphingomonas, or Ochrobactrum, has e.g. an ability to degrade at least ethynylestradiol among female sex hormones; and/or an ability to degrade at least17beta-estradiol and/or estrone among female sex hormones, and having a degradation rate constant k1 for 17beta-estradiol and/or estrone of at least0.05.    USE - The invention is useful for a degradation treatment of a female sex hormone, which is ethynylestradiol, 17beta-estradiol, estrone, and/or estriol, in wastewater. It is for use in a female sex hormone degrading agent (claimed). It is useful for treatment of sludge, such as raw sludge, excess sludge, return sludge, thickened sludge, and anaerobic digested sludge; and human wastes. Wastewater includes domestic wastewater, such as sewage or stockbreeding wastewater. The invention is useful for water separated from sludge, such as filtered water or recycle flow water.    ADVANTAGE - The invention can efficiently degrade female sex hormones, to such very low concentrations as not to affect the environment, and which can easily be cultured and proliferated. By use of the invention, treatment of female sex hormone in a vast amount of e.g. wastewater is provided at a low cost.    DETAILED DESCRIPTION - Female sex hormone degrading bacteria belonging to Novosphingobium, Sphingomonas, or Ochrobactrum, has an ability to degrade at least ethynylestradiol among female sex hormones; an ability to degrade at least17beta-estradiol and/or estrone among female sex hormones, and having a degradation rate constant k1 for 17beta-estradiol and/or estrone of at least0.05; and/or an ability to degrade at least17beta-estradiol and/or estrone among female sex hormones, and having an ability to decrease a concentration of 17beta-estradiol and/or estrone, contained in an object to be treated to less than 10 ng/L. An INDEPENDENT CLAIM is also included for degradation treatment of a female sex hormone, comprising bringing the female sex hormone degrading bacteria or a carrier having the bacteria immobilized on it, into contact with the female sex hormone.    DESCRIPTION OF DRAWING(S) - The figure shows changes in the concentration of 17beta-estradiol in batch treatment experiments using the bacteria.