To provide an antenna device that can reduce null point while suppressing high cost.

An antenna device 1 includes an antenna 2 disposed vertically on a printed circuit board 10. The antenna 2 includes two loop antennas 41 and 42 disposed on surfaces orthogonal to each other. The loop antennas 41 and 42 are respectively comprised of: standing antenna parts 21 and 22 disposed vertically on the printed circuit board 10; and substrate antenna parts 31 and 32 disposed on the printed circuit board 10. The standing antenna parts 21 and 22 share a part 201 (common part) extended from a first terminal 302 connected to a feeding point 301, and are formed so as to branch from the common part 201 onto different surfaces. The printed circuit board 10 is provided with a swith 54 that allows second terminals 303 and 304 of the loop antennas 41 and 42 to alternately be in continuity with ground by using an intermittent signal as a trigger.