Abstract: Disclosed is an electro-osmotic dehydrator dehydrating sludges generated from the treatment plants of, such as, pure water, sewage water, night soil, waste water, etc. using three phase alternating current. More particularly, the present invention is directed to an electro-osmotic dehydrator using three phase alternating current having three technical configurations as described below. (i) An electrode allowing voltage to be applied to a drum and a caterpillar comprises a spring and a graphite elastic supported by the spring, such that stable contact is possible regardless of the amount or constellation of sludges, and even abrasions of the electrode are progressing, the contact maintains always constant, thereby persisting the function of dehydration.