PROBLEM TO BE SOLVED: To provide an electrolytic device which can easily treat water to be treated and remarkably improve an inconvenience due to clogging of electrodes with garbage mixed in the water to be treated, a water treatment device using it, and a hydroponic culture system using them. SOLUTION: The water treatment device has a pair of electrodes 11, 12 each comprising at least a water-permeable member that can collect at least microorganisms and disposed so as to leave a prescribed space between them, water to be treated discharge pump 5 that discharges the water to be treated from between both electrodes 11, 12 after passing the water to be treated through each of the electrodes 11, 12 to make the water to be treated flow into between both electrodes 11, 12 from outside of them, and a control device 15 that controls potential impression to both electrodes 11, 12 and the discharge pump 5. COPYRIGHT: (C)2005,JPO&NCIPI
