A treatment method of organic compounds included in waste water, comprising the steps of: supplying waste water to an adsorber 2 filled with an adsorbent 3 therein for adsorbing the organic compounds in the waste water by the adsorbent 3 in the adsorber 2, supplying a current between an anode 9 and a cathode 8 in water including an electrolyte in an electrolyzer 6 for electrolyzing the water including an electrolyte, and supplying an electrolyte resulting from electrolysis in the electrolyzer 6 to the adsorbent 3 in the adsorber 2 for contacting the electrolyte with the adsorbent 3, so that the organic compounds adsorbed by the adsorbent 3 are desorbed or decomposed.