An antenna device includes a wiring board, a conductive member including a first conductor portion and a second conductor portion electrically connected to each other, a coil element including a coupling coil to be connected to a feed circuit, and a capacitor. The first conductor portion includes a conductor opening and a gap that connects the conductor opening and an outer edge of the first conductor portion, and the capacitor crosses the gap. The second conductor portion is connected to two points of an inner edge of the conductor opening, and, together with a portion of the first conductor portion and the capacitor, defines a loop-shaped current path. The coupling coil is magnetically coupled to the loop-shaped current path.