To provide a streamlined method of purifying brine for electrolysis.

The method of purifying brine for electrolysis comprises dissolving a raw salt in water, adding a flocculating agent to the obtained crude brine, filtering the resultant crude brine and carrying a chelating resin treatment so that divalent metal ions are removed from the crude brine, wherein after the addition of the flocculating agent and before the filtration, an alkali agent is added to the crude brine so that the pH value is adjusted to fall within the range of 7.5 to 9.5 and thereafter the removal of divalent metal ions is carried out without changing the pH value of the crude brine.