An electrode composite body includes: an active material molded body including active material particles which include a lithium composite oxide and have a particle shape, and a communication hole that is provided between the active material particles; a first solid electrolyte layer that is provided on a surface of the active material molded body, and includes a first inorganic solid electrolyte; and a second solid electrolyte layer that is provided on the surface of the active material molded body, and includes a second inorganic solid electrolyte of which a composition is different from a composition of the first inorganic solid electrolyte, and which contains boron as a constituent element and is amorphous.