A foldable portable radio device adapted to a plurality of frequency bands has a good antenna performance in all the use frequency bands even in both open and folded states. In the foldable portable radio device, a control section (24) controls switching means (20) to connect a sub-matching circuit (19) and a first circuit element (21) when a first use frequency band is used and further when the foldable portable radio device is in the open state and to connect the sub-matching circuit (19) and a second circuit element (22) when a first use frequency band is used and further when the foldable portable radio device is in the closed state, or when a second use frequency band is used irrespective of the open/closed state of the foldable portable radio device.