An antenna device for generating a reconfigurable high-order mode conical beam, includes a micro-strip radiator having multiple feeding points, wherein one of the feeding points is a fixed feeding point, and a feeding unit for providing two signals having a same amplitude and a preset phase difference, wherein one of the two signals is fed through the fixed feeding point and the other is fed through any one of remaining feeding points. A mode reconfigurable switching unit, connected to the feeding unit, performs a switching operation to select any one of the remaining feeding points so that the other signal is feed through the selected feeding point in accordance with mode control data.