To provide an antenna device for effectively utilizing an antenna containing space provided in a case of a mobile device and capable of ensuring communication characteristics.

Ends of an antenna 31 and both antennas 32, 33 are spaced and arranged. Thus, production of interlinked magnetic flux and then production of mutual coupling among the antenna 31 and both the antennas 32, 33 can be suppressed. Further, the antennas 31 to 34 are respectively arranged so that a line segment passing through midpoints P1 to P3 of the antenna 31 and both the antennas 32, 33 in their axial line direction and orthogonal to an axial line of the antenna 34 takes an angle of 90 degrees with respect to an axial line of the antenna 31 and both the antennas 32, 33. Thus, production of mutual coupling among the antennas 31 to 33 and the antenna 34 can be suppressed and the reduction in the sensitivity of the antenna device 15 can be suppressed.

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