To suppress the radiation of a high frequency in accordance with the length of transmission lines by reducing a common-mode current component on the transmission line.
In a reader/writer 31, a common-mode choke coil 51 is inserted between the transmission lines L11 and L12. Since a magnetic flux occurs in the common-mode choke coil 51 in the direction in which drive current caused to flow through the transmission line L11 and drive current caused to flow through the transmission line L12 negate each other by current Ic (common-mode current component) for a difference in an absolute value between the drive current through the transmission line L11 and the drive current through the transmission line L12. Namely, as a result of this, the radiation of the high frequency caused by the current Ic from the loop antenna 11 is suppressed.
SUZUKI MAMORU
YOSHIDA YUKO
MIYAGAWA YOICHI
