Realized are a high-performance electrochemical element and solid oxide fuel cell in which the contact properties between a dense and highly-gastight electrolyte layer and an electrode layer are improved while the treatment temperature during formation of the electrolyte layer is suppressed to a low temperature, and methods for producing the same. An electrochemical element includes an electrode layer 3, and an electrolyte layer 4 arranged on the electrode layer 3, wherein the electrode layer 3 has a plurality of pores that are open on a face thereof in contact with the electrolyte layer 4, and the pores are filled with fine particles made of the same components as the electrolyte layer 4.