Abstract: An automatic oxidation-reduction treatment system, characterized in that it comprises introducing oxygen or hydrogen to a agitation vessel under reduced pressure through a nozzle to feed the gas into a solution having a reduced pressure and reduce the size of a bubble by agitation under reduced pressure, subjecting the resultant solution to high speed agitation by means of a water-jet pump under reduced pressure to further reduce the size of a bubble, and rapidly feeding the resultant bubbles into an agitation vessel under pressure to dissolve the bubble while still further reducing the size of a bubble under pressure by instantaneously cutting and pressing it, thereby convert the solution into a colloidal state.