An antenna (100) includes a ground plate (110) and a radiating element (130) that has a shape expanding in a predetermined expansion direction and a self-similar shape with respect to an end portion (135) connected to a feeding line (151) that is a feeding portion. The radiating element (130) is arranged in a standing state relative to the end portion (135) so as to face the end portion (135) toward the ground plate (110). In addition, the radiating element (130) has a first radiating element portion (131) and a second radiating element portion (133) that are plane-symmetric to each other across a predetermined virtual symmetric plane (A1) along the expansion direction, and thereby forms a shape expanded in the expansion direction.