There are provided an antenna element and a portable radio that enable miniaturization, acquisition of a high gain, and broadening of a band and that copies compatible with multiple bands. A rectangular-parallelepiped-shaped antenna element is formed by folding two or more faces of a board-shaped monopole element having an rectangular shape so that the antenna element has a substantially rectangular first conductor plate 51 disposed in proximity to a hinge 4 while arranged at a predetermined space S from a lower circuit board (ground plate) 21, a substantially rectangular second conductor plate 52 that shares a widthwise one side of the first conductor plate 51 and that is arranged while bent to an angle of about 90° with respect to the first conductor plate, and a substantially rectangular third conductor plate 53 that shares another widthwise side of the second conductor plate 52 opposing the side shared by the first conductor plate 51 and the second conductor plate 52 and that is arranged at an angle of about 90° so as to oppose the first conductor plate 51.