To provide a water treatment apparatus which is used for treating raw water containing an anionic surfactant and in which the decrease of a chemical oxygen demand (COD) can be efficiently achieved.

The water treatment apparatus in which raw water containing the anionic surfactant is treated, is provided with: a flocculation treatment means for flocculating raw water; a pH adjustment means for adjusting the pH of the raw water to 3-5.5 in the flocculation treatment; and an activated carbon adsorption means for performing the activated carbon adsorption treatment of the flocculated liquid which is obtained by flocculating the raw water.