An antenna device includes a retaining seat, a first polarized antenna module, and a second polarized antenna module, both disposed on the retaining seat. The first polarized antenna module has a dual-band monopole antenna. The second polarized antenna module has a carrying frame disposed on the retaining seat, two dual-band dipole antennas in a coplanar arrangement formed on the carrying frame, and a splitter installed on the carrying frame. Each dual-band dipole antenna defines a longitudinal axis and has a feeding and a grounding segment arranged in the longitudinal axis. The longitudinal axes of the dual-band dipole antennas are perpendicular to each other. The polarized direction of the dual-band dipole antennas is perpendicular to the polarized direction of the dual-band monopole antenna. The splitter is electrically connected to the feeding segments for separating a current respectively into the feeding segments by a phase difference of 90 degrees.