A radio communication device includes a mounting substrate and a shielding case to cover circuits mounted on the substrate. A first surface of the substrate includes an input/output area where a transmitting/receiving unit of an RF signal is mounted, an amplification area where an amplifying unit to amplify the RF signal from the transmitting/receiving unit is mounted, an RF area where an RF processing unit to process the. RF signal is mounted, and a baseband area where a baseband processing unit to process a baseband signal is mounted. A second surface of the substrate includes a crystal oscillator arranged to generate a reference clock signal which is supplied to the RF processing unit and the baseband processing unit.