A composite module is obtained which enables high-density mounting of components without increasing its size. A composite module includes a main substrate which is a multilayer circuit board, a sub-substrate mounted on a lower surface of the main substrate, a sealing layer arranged on the lower surface of the main substrate to cover the sub-substrate, the sealing layer defining a mount surface arranged to be mounted on a mount board, and terminal electrodes disposed on the mount surface. The terminal electrodes include at least one first terminal electrode drawn directly from the main substrate and at least one second terminal electrode drawn directly from the sub-substrate.