Disclosed is a mobile wireless device, which has an antenna structure for feeding a hinge core with an electric power and which can be adapted to wireless communications of low-frequency bands without enlarging a casing itself. In this wireless device, an upper casing (101) equipped with a first circuit substrate (111) and a lower casing (102) equipped with a second circuit substrate (112) having a wireless unit (118) mounted thereon are connected to open and close through a hinge unit having a conductive hinge (130). A feeding unit (113) mounted in the upper casing (101) feeds the conductive hinge (130) with an electric power from the first circuit substrate (111). A cellular antenna (150) mounted in the lower casing (102) is connected with the ground pattern of the second circuit substrate (112) at the position, where an extension (154) is separated along the axial direction of the conductive hinge (130) from a capacity coupling unit (152) arranged to confront a portion of the conductive hinge (130) and coupled capacitively to a portion of the conductive hinge (130), thereby to short-circuit the capacity coupling unit (152) and the ground pattern.