A diplexer capable of passing signals of a high frequency band without being attenuated over a wide frequency band, and a high-frequency switch using the diplexer are provided. Based on the physical idea that white light emission can be achieved by regulating the relative luminous intensities of blue- and orange-light emitting units located in a single polymer molecule, the present invention provides three types of high efficiency and stable white electroluminescent polymeric material systems. The coil, the electrolytic capacitor and the microprocessor, which should not be sealed with resin, are mounted in the resin-free region, while the board and the electronic parts which are not capped by the cover are sealed with a resin. The storage member is arranged so that the inner compartment is proximal to the structure as compared to the outer compartment.