An antenna structure with a wide beamwidth includes a dielectric substrate, a ground plane, a first radiation element, a plurality of first conductive via elements, and a first feeding connection element. The dielectric substrate has a first surface and a second surface which are opposite to each other. The ground plane is disposed on the second surface of the dielectric substrate. The first radiation element is disposed on the first surface of the dielectric substrate. A first notch is formed on the first radiation element. The first conductive via elements penetrate the dielectric substrate. The first conductive via elements are coupled between the first radiation element and the ground plane. The first feeding connection element is coupled to the first radiation element. The first feeding connection element extends into the first notch of the first radiation element.