A module substrate defined by an aggregate substrate is prepared, and circuit components are mounted on the module substrate. An insulating resin layer is formed on substantially the entire top surface of the module substrate such that the circuit components are disposed in the insulating resin layer, and a top-surface-shielding layer is formed on the top surface of the insulating resin layer. First through holes are formed in the module substrate and the insulating resin layer at locations corresponding to portions of boundary lines of small substrates so as to extend in a thickness direction of the module substrate and the insulating resin layer. First electrode films are formed on the inner surfaces of the first through holes so as to be connected to the first shielding layer, and the first through holes are filled with a filling material. Next, second through holes are formed at locations corresponding to the remaining portions of the boundary lines of small substrates so as to extend in the thickness direction, and second electrode films are formed on the inner surfaces of the second through holes so as to be connected to the top-surface-shielding layer and the first electrode films. The filling material, with which the first through holes are filled, is cut along the boundary lines of small substrates, resulting in a division of the aggregate substrate into small substrates to obtain circuit modules.