PROBLEM TO BE SOLVED: To provide a body of production supply water having an abated silica content by abating the silica concentration at a low chemical dispensation ratio and by greatly ameliorating the solid-liquid separability of a silica-containing sludge.SOLUTION: The provided problem-solving silica removal method is a method for removing silica from a body of neutral or alkaline silica-containing treatment target water including the obtainment of treated water by adding a divalent metal salt to the treatment target water and by subsequently adding thereto an alkali agent so as to separate the silica therefrom, whereas the alkali agent is added neither simultaneously with the addition of the divalent metal salt nor immediately after the addition of the divalent metal salt.
