PURPOSE: A relay device for mobile communication is provided to output a frequency not used for mobile communication while reducing production costs. CONSTITUTION: A remote radio head (110) receives a signal of a first frequency from a digital unit. The remote radio head converts the frequency of the signal into a second frequency. A master unit (120) receives a signal of the second frequency from the remote radio head. The master unit converts the second frequency into an intermediate frequency. A slave unit (130) receives a signal of the intermediate frequency from the master unit. The slave unit converts the signal into the first frequency.
