Abstract: Embodiments of this application provide a radiation apparatus and a multi-band array antenna, and relate to the field of antenna technologies. The radiation apparatus includes a radiation module, a first conductor balun, and a second conductor balun. The first conductor balun is mechanically connected to the second conductor balun under the radiation module. The radiation module includes a first radiation unit and a second radiation unit in a +45° polarization direction, and a third radiation unit and a fourth radiation unit in a ?45° polarization direction. The first conductor balun is configured to feed a first differential signal to the first radiation unit and the second radiation unit. The second conductor balun is configured to feed a second differential signal to the third radiation unit and the fourth radiation unit. The first conductor balun and the second conductor balun are disposed in the same plane.