In the magnesium recovery method and magnesium recovery apparatus, anode electrolyzed water (7a) and cathode electrolyzed water (7b) produced by electrolysis of seawater are separated, alkaline material is inputted into the anode electrolyzed water to adjust pH, magnesium is precipitated as magnesium hydroxide in the cathode electrolyzed water, and recovered, and the anode electrolyzed water after pH adjustment and cathode electrolyzed water after carbonate fixation are intermixed, and discharged in a state where a pH of the intermixed water is identical to a pH of the seawater. As a result, magnesium can be recovered from seawater while minimizing impact on the environment.