An electrochemical element (Q) has a metal substrate (1) and multiple electrochemical reaction portions. The metal substrate (1) has gas flow allowing regions that allow the flowing of a gas between the upper side (4) and the lower side (5) of the metal substrate (1). The electrochemical reaction portions each have at least an electrode layer (A), an electrolyte layer (B), and a counter electrode layer (C), and are arranged on the upper side (4) of the metal substrate (1). The electrolyte layer (B) is arranged between the electrode layer (A) and the counter electrode layer (C), and the gas flowing through the gas flow allowing regions is supplied to the electrode layer (A).