An object of the present invention is to secure good communication quality in a small-housing portable radio in which an antenna system having two antenna elements for providing for multi-frequency-bands is built. A substrate on which a high-frequency circuit and an earth plate are mounted and an antenna system is built in the housing of a portable radio device. A shorter coil element of two coil elements is set so that the direction of the antenna current is vertical to one side of a substrate and the longer coil element is set so that the direction of the antenna current is parallel with the side. Therefore, it is possible to set two coil elements in a small space in a housing after setting the substrate while directions of the antenna currents of the coil elements are orthogonal to each other (while mutual interference between the elements is small). Therefore, it is possible to secure good communication quality even for a small-housing portable radio device.