A composite electronic component that prevents the electrical connection between a conductive case member of the composite electronic component, which performs physical shielding against a physical impact or dust adhesion and also performs an electromagnetic shielding function, and a conductive member for performing the electromagnetic shielding function for a surface acoustic wave element built therein. A composite electronic component includes surface acoustic wave devices therein, a first case member, and a second metallic case member. In order to prevent the electrical connection between the internal surface of the metallic case connected to a ground potential and a conductor disposed in a package of the surface acoustic wave devices and connected to the ground potential to perform the electromagnetic shielding function, an insulating material layer is provided on at least one of the top surface of the conductor and the bottom surface of a top plate of the metallic case.