An apparatus for continuously electrolyzing waste liquid, comprising: a series of tanks comprising a plurality number n (n represents an integer equal to or greater than 2) of electrolytic tanks (10A, 10B) each having an anode and a cathode, the electrolytic tanks being connected in series; vibrating flow generating means which is equipped to each of said electrolytic tanks and generates vibrating flow in waste liquid to be treated; and a power supply circuit for applying a voltage between said anode and said cathode, wherein the distance between said anode and said cathode is set to 10 to 40 mm, and said vibrating flow generating means comprises vibration generating means; vibration transmitting rods which are operationally connected to said vibration generating means so as to vibrate in the waste liquid to be treated; and vibrating vanes fixed to said vibration transmitting rods; wherein plural electrolytic tanks constituting said series of tanks are unified, and said electrolytic tanks thus unified are partitioned by respective partition walls; wherein a chute is equipped between the respective continuous electrolytic tanks thus unified so that the waste liquid to be treated is fed from one electrolytic tank to the other electrolytic tank; wherein said chute is equipped with a flow-in cut-out portion into which the waste liquid to be treated flows from the one electrolytic tank of said continuous electrolytic tanks of the unified electrolytic tanks, and a flow-out cut-out portion from which the waste liquid to be treated flows out to the other electrolytic tank of said continuous electrolytic tanks of the unified electrolytic tanks; wherein the one electrolytic tank of said continuous electrolytic tanks of the unified electrolytic tanks is equipped with a dam adjacently to said flow-in cut-out portion; and wherein said vibration generating means is used commonly by plural vibrating flow generating means. a series of tanks comprising a plurality number n (n represents an integer equal to or greater than 2) of electrolytic tanks (10A, 10B) each having an anode and a cathode, the electrolytic tanks being connected in series; vibrating flow generating means which is equipped to each of said electrolytic tanks and generates vibrating flow in waste liquid to be treated; and a power supply circuit for applying a voltage between said anode and said cathode, wherein the distance between said anode and said cathode is set to 10 to 40 mm, and said vibrating flow generating means comprises vibration generating means; vibration transmitting rods which are operationally connected to said vibration generating means so as to vibrate in the waste liquid to be treated; and vibrating vanes fixed to said vibration transmitting rods; wherein plural electrolytic tanks constituting said series of tanks are unified, and said electrolytic tanks thus unified are partitioned by respective partition walls; wherein a chute is equipped between the respective continuous electrolytic tanks thus unified so that the waste liquid to be treated is fed from one electrolytic tank to the other electrolytic tank; wherein said chute is equipped with a flow-in cut-out portion into which the waste liquid to be treated flows from the one electrolytic tank of said continuous electrolytic tanks of the unified electrolytic tanks, and a flow-out cut-out portion from which the waste liquid to be treated flows out to the other electrolytic tank of said continuous electrolytic tanks of the unified electrolytic tanks; wherein the one electrolytic tank of said continuous electrolytic tanks of the unified electrolytic tanks is equipped with a dam adjacently to said flow-in cut-out portion; and wherein said vibration generating means is used commonly by plural vibrating flow generating means.