An antenna device and a method of manufacturing the antenna device are provided. The antenna device includes a circuit board, a chip, an encapsulation layer, and an antenna. The circuit board includes an insulation substrate having an upper surface, a lower surface, and a groove formed on the upper surface; a conductive circuit disposed in the insulation substrate; a first conductive pad disposed in the insulation substrate, connected to the conductive circuit, and exposed from the lower surface; a second conductive pad connected to the conductive circuit, and exposed from the groove; and a third conductive pad exposed from the groove. The chip is disposed in the groove, connected to the second conductive pad, and coupled to the third conductive pad. The encapsulation layer is disposed in the groove, and covers the chip.