ANTENNA DEVICE

PROBLEM TO BE SOLVED: To provide an antenna device capable of flexibly adjusting resonance frequencies forming a double resonance state.SOLUTION: An antenna device includes: a substrate body; a ground pattern GND formed on a surface of the substrate body; and first to third elements 3 to 5. In the first element, a feeding point FP is provided at the base end side. The first element extends in a constant direction with first passive elements P1a, P1b and an antenna element AT connected with a middle part of the first element. The second element extends along the first element with a base end of the second element connected with the base end side of the first element. A third element includes at least a fifth extending part E5 extending in a direction opposite to the first element.