A dielectric antenna of the present invention includes a pillar-shaped dielectric section for radiating an electromagnetic wave being fed thereto. The dielectric section includes a depressed portion in an upper portion thereof. The vertical cross section of the depressed portion has such a shape that the height of the dielectric section gradually increases toward the side surface of the dielectric section. For example, the depressed portion is a notch having a V-shaped vertical cross section. Alternatively, the depressed portion includes a flat surface portion.