In the antenna unit employed in a radio paging receiver, a helical antenna 1 which is positioned along one side of a circuit substrate 4 on which a receiver circuit 3 is mounted and has a main polarization direction formed by a single body of the helical antenna 1 in the Z-axis direction, and a dipole antenna which has a main polarization direction formed by the helical antenna 1 and the circuit substrate 4 on the Y-axis direction are constructed. The non-directional direction characteristic which has a high antenna gain in all directions in the free space by compensating null points in the directivity mutually with use of the antennas whose main polarization directions are intersected substantially orthogonally.