An apparatus for generating electrolyzed water comprising an anode plate, a first porous cathode plate and a second porous cathode plate, wherein the first cathode plate and the second cathode plate are provided on opposite sides across the anode plate; a first electrolysis chamber is formed between the anode plate and the first cathode plate, a second electrolysis chamber is formed between the anode plate and the second cathode plate, a third electrolysis chamber is formed on the side of the first cathode plate opposite to the anode plate, and a fourth electrolysis chamber is formed on the side of the second cathode plate opposite to the anode plate; wherein being "porous" means that the first porous cathode plate and the second cathode plate have a plurality of holes that form water flow paths allowing ions to enter and exit between the first electrolysis chamber and the third electrolysis chamber and between the second electrolysis chamber and the fourth electrolysis chamber, respectively; the anode plate being an anode plate that can block the entrance and exit of water between the first electrolysis chamber and the second electrolysis chamber; in each of the first electrolysis chamber and the second electrolysis chamber, an ion-exchange membrane (31, 32) is arranged to be in contact with the cathode plate (21, 22) so as to form a space allowing water to flow between the anode plate and the ion-exchange membrane (31, 32); a first water path is formed such that water is fed to the first electrolysis chamber, passes through the first electrolysis chamber and then discharged therefrom; a second water path is formed such that water is fed to the second electrolysis chamber, passes through the second electrolysis chamber and then discharged therefrom; and a third water path is formed such that water is fed to either one of the third electrolysis chamber and the fourth electrolysis chamber, the treated water discharged by passing the electrolysis chamber (103, 104) is fed to the other electrolysis chamber (104, 103), passes through the other electrolysis chamber (104, 103) and then discharged therefrom; wherein a tortuous water path is formed in the first electrolysis chamber, the second electrolysis chamber, the third electrolysis chamber and the fourth electrolysis chamber by providing a packing having a tortuous water path formed thereon, or a water guiding plate forming a tortuous water path. wherein the first cathode plate and the second cathode plate are provided on opposite sides across the anode plate; a first electrolysis chamber is formed between the anode plate and the first cathode plate, a second electrolysis chamber is formed between the anode plate and the second cathode plate, a third electrolysis chamber is formed on the side of the first cathode plate opposite to the anode plate, and a fourth electrolysis chamber is formed on the side of the second cathode plate opposite to the anode plate; wherein being "porous" means that the first porous cathode plate and the second cathode plate have a plurality of holes that form water flow paths allowing ions to enter and exit between the first electrolysis chamber and the third electrolysis chamber and between the second electrolysis chamber and the fourth electrolysis chamber, respectively; the anode plate being an anode plate that can block the entrance and exit of water between the first electrolysis chamber and the second electrolysis chamber; in each of the first electrolysis chamber and the second electrolysis chamber, an ion-exchange membrane (31, 32) is arranged to be in contact with the cathode plate (21, 22) so as to form a space allowing water to flow between the anode plate and the ion-exchange membrane (31, 32); a first water path is formed such that water is fed to the first electrolysis chamber, passes through the first electrolysis chamber and then discharged therefrom; a second water path is formed such that water is fed to the second electrolysis chamber, passes through the second electrolysis chamber and then discharged therefrom; and a third water path is formed such that water is fed to either one of the third electrolysis chamber and the fourth electrolysis chamber, the treated water discharged by passing the electrolysis chamber (103, 104) is fed to the other electrolysis chamber (104, 103), passes through the other electrolysis chamber (104, 103) and then discharged therefrom; wherein a tortuous water path is formed in the first electrolysis chamber, the second electrolysis chamber, the third electrolysis chamber and the fourth electrolysis chamber by providing a packing having a tortuous water path formed thereon, or a water guiding plate forming a tortuous water path.