Chromium-containing water treatment method

The present invention provides a chromium-containing water treatment method that allows treatment of water that contains chromium (chromium-containing water) at low cost. A chromium-containing water treatment method according to the present invention comprises: a reduction step in which chromium-containing water 11 and a liquid 12 containing 5-50 ppm of hydrogen sulfide are mixed, and the mixture is adjusted to pH 3.5 or lower and ORP 200-400 mV by adding an acid 13 thereto, so as to reduce chromium contained in the water; and a precipitation separation step in which a neutralizing agent is added to a solution 11' obtained via the reduction step so as to adjust the solution 11' to pH 8-9, thereby precipitating and separating, as a hydroxide, the reduced chromium contained in the solution.