An antenna device (10, 10A, 10B, 10C, 10D, 10E, 10F, 10G) comprising at least: a plurality of rod-shaped cores (20, 20A, 20B, 20C, 20D, 100A, 100B, 202A, 202B), arranged in series; a first coil formed by winding a conductive wire around the outer circumferential side of a first rod-shaped core (20A, 20C, 100A, 202A) which is selected from the plurality of rod-shaped cores (20, 20A, 20B, 20C, 20D, 100A, 100B, 202A, 202B); a second coil formed by winding a conductive wire around the outer circumferential side of a second rod-shaped core (20B, 20D, 100B, 202B) which is selected from the plurality of rod-shaped cores (20, 20A, 20B, 20C, 20D, 100A, 100B, 202A, 202B) and said second rod-shaped core is arranged to either one side of the end-portions of the first rod-shaped core (20A, 20C, 100A, 202A), wherein an end surface (26A, 28A) of the first rod-shaped core (20A, 20C, 100A, 202A), close to which the second rod-shaped core (20B, 20D, 100B, 202B) is arranged, is spaced from an end surface (26B, 28B)of the second rod-shaped core (20B, 20D, 100B, 202B), close to which the first rod-shaped core (20A, 20C, 100A, 202A) is arranged, wherein a flange portion is provided at the end portion of the first rod-shaped core (20A, 20C, 100A, 202A), close to which the second rod-shaped core (20B, 20D, 100B, 202B) is arranged, and wherein a flange portion is provided at the end portion of the second rod-shaped core (20B, 20D, 100B, 202B), close to which the first rod-shaped core (20A, 20C, 100A, 202A) is arranged, characterized by the plurality of rod-shaped cores (20, 20A, 20B, 20C, 20D, 100A, 100B, 202A, 202B) being made of a magnetic material. a plurality of rod-shaped cores (20, 20A, 20B, 20C, 20D, 100A, 100B, 202A, 202B), arranged in series; a first coil formed by winding a conductive wire around the outer circumferential side of a first rod-shaped core (20A, 20C, 100A, 202A) which is selected from the plurality of rod-shaped cores (20, 20A, 20B, 20C, 20D, 100A, 100B, 202A, 202B); a second coil formed by winding a conductive wire around the outer circumferential side of a second rod-shaped core (20B, 20D, 100B, 202B) which is selected from the plurality of rod-shaped cores (20, 20A, 20B, 20C, 20D, 100A, 100B, 202A, 202B) and said second rod-shaped core is arranged to either one side of the end-portions of the first rod-shaped core (20A, 20C, 100A, 202A), wherein an end surface (26A, 28A) of the first rod-shaped core (20A, 20C, 100A, 202A), close to which the second rod-shaped core (20B, 20D, 100B, 202B) is arranged, is spaced from an end surface (26B, 28B)of the second rod-shaped core (20B, 20D, 100B, 202B), close to which the first rod-shaped core (20A, 20C, 100A, 202A) is arranged, wherein a flange portion is provided at the end portion of the first rod-shaped core (20A, 20C, 100A, 202A), close to which the second rod-shaped core (20B, 20D, 100B, 202B) is arranged, and wherein a flange portion is provided at the end portion of the second rod-shaped core (20B, 20D, 100B, 202B), close to which the first rod-shaped core (20A, 20C, 100A, 202A) is arranged, characterized by the plurality of rod-shaped cores (20, 20A, 20B, 20C, 20D, 100A, 100B, 202A, 202B) being made of a magnetic material.