An antenna device is provided in the invention and includes a first rod-shaped core (20A) having a flange portion (22A) and a second rod-shaped core (20B) having a flange portion (22B), which are arranged in series and including a first coil (30A) and a second coil (30B), wherein the end surface (26A) of the first rod-shaped core (20A) and the end surface (26B) of the second rod-shaped core (20B)are spaced. The antenna device can help suppress fluctuation of inductance.