Radio terminal device antenna and radio terminal device

A radio terminal device has an antenna element, a coil, a switch, an RF circuit section and a conductive substrate. The switch is used to switch between a case where current distribution exists only in the antenna element and its vicinities and a case where the current distribution exists not only in the antenna element and its vicinities but also in other places. Additionally, the switch is switched in accordance with the usage pattern in which the user uses the radio terminal device (e.g., telephone call and data communication). This allows the transmission/reception to be performed with the antenna polarization and directivity suitable for the usage pattern. Thus, there can be provided a radio terminal device that exhibits a reception characteristic suitable for a respective situation.