A purification method for spent fuel pool water from nuclear power generation, the method comprising: passing the water at a linear flow velocity of 50 m/h or less through a purification apparatus for the water comprising an ion exchange resin layer and a metal-doped resin layer which is laid at a bed height of 2 cm or more on a surface layer of the ion exchange resin layer wherein the water to be treated is contacted with the metal-doped resin layer to decompose a pro-oxidant contained in the water; and subsequently contacting the water with the ion exchange resin.