An antenna device includes a first antenna element and a second antenna element. The first antenna element operates at a first predetermined frequency band. The second antenna element operates at a second predetermined frequency band that is different from the first predetermined frequency band. The first antenna element includes a base end portion, a front end portion, a folded portion, a first side portion disposed between the base end portion and the folded portion, and a second side portion disposed between the folded portion and the front end portion. A direction of a current vector in the first side portion is equal to a direction of a current vector in the second side portion. The second antenna element is disposed adjacent to the first antenna element.