An antenna device configured to emit an electromagnetic wave with a tilted orientation that is tilted by a tilt angle θ with respect to a front direction of the antenna device, the antenna device comprising: a feeding unit configured to feed the electromagnetic wave; a ground conductor; a substrate having a first plane on which the feeding unit is formed and a second plane on which the ground conductor is formed, the second plane being opposite to the first plane, wherein the front direction of the antenna device corresponds to a direction perpendicular to the first plane of the substrate; a feed line having one end coupled with the feeding unit, the feed line being a strip conductor formed on the first plane; and N radiation elements (5-1,..., 5-4) formed by a strip conductor in the feed line, the radiation elements (5-1,..., 5-4) comprising one or more coupling portions to the feed line, wherein N is an integer greater than or equal to 2, wherein the radiation elements (5-1,..., 5-4) are arranged at unequal intervals; wherein each of a first to an (N - 1)th radiation elements (5-1,..., 5-3) out of the N radiation elements (5-1,..., 5-4), when counted from the feeding unit side, is formed with a first recessed portion (c1b,..., c3b) at one of two coupling portions (5-1b,..., 5-3b) to the feed line that is on an opposite side of the feeding unit; wherein line lengths of the feed line between the N radiation elements (5-1,..., 5-4) and each recess amount of the first and second recess portions (c3a, c4a, c1b,..., c3b) configure the antenna device to emit the electromagnetic wave with the tilted orientation; wherein one or more radiation elements (5-1, 5-2) out of the N radiation elements (5-1,..., 5-4) are formed with a hole (8-1, 8-2), wherein no such hole is formed in one or more other radiation elements (5-3, 5-4) out of the N radiation elements (5-1,..., 5-4), wherein each of the one or more radiation elements (5-3, 5-4) provided with no such hole is formed with a second recessed portion (c3a, c4a) at the other of the two coupling portions (5-3a, 5-4a) on the feeding unit side, and wherein the one or more radiation elements (5-1, 5-2) provided with the holes (8-1, 8-2) are configured to have higher input impedances as compared to the one or more other radiation elements (5-3, 5-4). a feeding unit configured to feed the electromagnetic wave; a ground conductor; a substrate having a first plane on which the feeding unit is formed and a second plane on which the ground conductor is formed, the second plane being opposite to the first plane, wherein the front direction of the antenna device corresponds to a direction perpendicular to the first plane of the substrate; a feed line having one end coupled with the feeding unit, the feed line being a strip conductor formed on the first plane; and N radiation elements (5-1,..., 5-4) formed by a strip conductor in the feed line, the radiation elements (5-1,..., 5-4) comprising one or more coupling portions to the feed line, wherein N is an integer greater than or equal to 2, wherein the radiation elements (5-1,..., 5-4) are arranged at unequal intervals; wherein each of a first to an (N - 1)th radiation elements (5-1,..., 5-3) out of the N radiation elements (5-1,..., 5-4), when counted from the feeding unit side, is formed with a first recessed portion (c1b,..., c3b) at one of two coupling portions (5-1b,..., 5-3b) to the feed line that is on an opposite side of the feeding unit; wherein line lengths of the feed line between the N radiation elements (5-1,..., 5-4) and each recess amount of the first and second recess portions (c3a, c4a, c1b,..., c3b) configure the antenna device to emit the electromagnetic wave with the tilted orientation; wherein one or more radiation elements (5-1, 5-2) out of the N radiation elements (5-1,..., 5-4) are formed with a hole (8-1, 8-2), wherein no such hole is formed in one or more other radiation elements (5-3, 5-4) out of the N radiation elements (5-1,..., 5-4), wherein each of the one or more radiation elements (5-3, 5-4) provided with no such hole is formed with a second recessed portion (c3a, c4a) at the other of the two coupling portions (5-3a, 5-4a) on the feeding unit side, and wherein the one or more radiation elements (5-1, 5-2) provided with the holes (8-1, 8-2) are configured to have higher input impedances as compared to the one or more other radiation elements (5-3, 5-4).