Terminal electrodes 9 for carrying a high frequency device 3 are formed on a surface of a circuit board having its reverse surface covered with a reverse surface conductor layer 6, and a plurality of signal lines 2 for exchanging a signal between the high frequency device 3 and an external circuit are formed thereon. The terminal electrode 9 is arranged at the center of the circuit board, and the signal lines 2 radially extends from the terminal electrode 9. Electromagnetic interference between the signal lines 2 can be reduced, so that out-of-band attenuation characteristics and isolation characteristics can be satisfactorily exhibited in a case where the high frequency device 3 is a duplexer.