In a surface-mount type antenna, a substantially-rectangular solid base body has a feeding terminal and a ground terminal formed on its one side surface. A radiating electrode has its one end connected to the ground terminal and is disposed helically across the surfaces of base body extending from one side surface to one principal surface. Another end of radiating electrode extends from one principal surface, through another side surface, toward another principal surface, to form a wide-area portion facing the feeding terminal. An antenna apparatus is constructed by mounting the surface-mount type antenna on a mounting substrate having formed thereon a feeding electrode, a ground electrode, and a ground conductor layer, and simultaneously connecting the feeding terminal and the ground terminal to the feeding electrode and the ground electrode, respectively.