There is provided is a method of manufacturing a superconductor layer, including preparing a coating solution by dissolving trifluoroacetates of at least one metal selected from the group consisting of yttrium and lanthanoids, barium, and copper in a solvent, coating a main surface of a substrate with the coating solution to form a coating film, subjecting the coating film to a calcining process in an atmosphere containing oxygen, and subjecting the coating film after the calcining process to a firing process in an atmosphere containing water vapor at a temperature higher than that at the calcining process. The calcining process is carried out such that the coating film after the calcining process and before the firing process have an average CuO particle diameter equal to or less than 25 nm.