An object is to provide a technique that can reduce the degradation in the characteristics of a transmitting filter by improving heat dissipation characteristics of a composite component having a stack structure. Since a transmitting filter is disposed in or on a first substrate 14, the heat generated in the transmitting filter is efficiently dissipated, for example, to an external module substrate 2 electrically connected to the first substrate 14. It is thus possible to reduce changes in the characteristics of the transmitting filter caused by a temperature rise. Thus, by improving heat dissipation characteristics of a composite component 10 having a stack structure, the degradation in the characteristics of the transmitting filter can be reduced.