An object of the present invention is to provide a portable radio apparatus that obtains a high antenna performance without limiting the degree of freedom in the exterior and design of a main body of portable radio apparatus. A portable radio apparatus (1) includes a radiation element (14) disposed on a side opposite to a rear part (10a) of a housing (10) through a circuit board (11), and a plate conductor (16) disposed substantially in parallel to the circuit board (11) between the circuit board (11) and the rear part (10a) of the housing (10). With the provision of the radiation element (14) and the plate conductor (16), when the portable radio apparatus (1) is put on a metal plate (300), the radiation element (14) operates as a vertical passive element having an electrical length of λ/2 with the help of an image current caused by the metal plate (300), and also the plate conductor (16) operates as a counterpoise of the radiation element (14), to thereby obtain a higher antenna performance on the metal plate (300). Also, since no rib for separating the antenna element (13) of the portable radio apparatus (1) from the metal plate is required, the degree of freedom in the exterior and design of the portable radio apparatus (1) main body is not limited.