Metal recovery method

Metal deposited by electrolysis is integrated with a negative electrode so as to be able to be solidified from wastewater. However, for actual recovery, it is necessary to extract the negative electrode and, for example, scrape off the surface thereof so as to recover the metal. A metal recovery method according to the present invention comprises: a treatment target solution injection step for injecting, into a container in which electrode plates are disposed, a solution containing metal which exists in an ionic state; a resting step for leaving the solution stationary with respect to the electrode plates; a sponge-like metal porous body formation step for supplying an electric current between the electrode plates and causing a sponge-like metal porous body to be formed on the electrode plate which has become a negative electrode; and a separation step for separating the sponge-like metal porous body from the electrode. The metal which has been deposited on the electrode is not fixed to the electrode plate, a