To provide a water treatment method by which water treatment can be efficiently carried out even in a neutral region and an alkali region without requiring much energy cost and a large-sized apparatus, and to provide a water treatment apparatus used for the water treating method.

A water treatment method is configured such that a streamer discharge is generated between a linear electrode 3 and a cylindrical electrode 4 which are provided in a treatment chamber 2, water W to be treated is made into water droplets and supplied in a discharge space, and substances to be treated in the water droplet M is subjected to decomposition treatment by active species generated by the discharge in the discharge space. At least either a water-soluble ferrous salt or its aqueous solution is added to at least one of the water W to be treated, treated water W1 obtained by making the water W to be treated into the water droplets and passing through the inside of the discharge space, and mixed water of the water W to be treated and the treated water W1.