An antenna apparatus and a wireless communications device, where the antenna apparatus includes a feeding part, a grounding part, and a closed frame, where the closed frame encircles a main body of the wireless communications device. The feeding part and the grounding part are electrically connected to the closed frame, and the closed frame, the feeding part, and the grounding part form a first current loop and a second current loop, where resonance is generated between the first current loop and the second current loop. There is no need to dispose a slit on the closed frame of the wireless communications device that uses a metal appearance, and a position of the feeding part of a radio frequency feeder is used, to mitigate impact, of a closed environment caused by not disposing the slit on the closed frame, on antenna radiation performance, thereby improving antenna performance and user experience.