ANTENNA DEVICE

PROBLEM TO BE SOLVED: To provide an antenna device in which each resonance frequency subjected to double resonance can be adjusted flexibly.SOLUTION: An antenna device comprises: a substrate body 2; and first element 3 and second element 4 formed on the surface of the substrate body. First passive elements P1a, P1b and an antenna element AT are connected to the way of the first element and extend therefrom. The first element has a first extension E1 extending in a fixed direction, a second extension E2 extending from the tip of the first extension in a direction orthogonal thereto, and a third extension E3 extending from the tip side of the second extension toward the proximal end side of the first extension along the first extension via a folding antenna element. The second element has a fourth extension E4 extending along the third extension from the proximal end of the first extension in a direction opposite from the first extension, and a fifth extension E5 extending from the tip of the fourth extension toward the third extension.