Antenna device with improved mounting structure

An antenna device comprising:

• an antenna substrate;
• and
• an antenna element that is connected to the antenna substrate, wherein
• the antenna element includes:
• an antenna unit that is arranged at a position separated by a predetermined length from a substrate surface of the antenna substrate in a first direction that is a direction perpendicular to the substrate surface of the antenna substrate, in such a way as to be parallel to the substrate surface of the antenna substrate;
• a grounding unit that is connected continuous to the antenna unit and grounded to the antenna substrate;
• and
• a feeding unit that is connected continuous to the antenna unit and feeds power to the antenna unit,
• the grounding unit is provided with a grounding body that is connected continuous to the antenna unit on one side in the first direction, and a mounting unit that is connected continuous to another side of the grounding body in the first direction and mounted on the antenna substrate, and
• the mounting unit is provided with a plurality of mounting pieces that are spaced apart along a second direction intersecting the first direction,
• wherein the grounding unit includes a plurality of directly opposing slits provided therein that extend in the second direction to define a narrow portion of the grounding body disposed between the plurality of directly opposing slits and a wide portion of the grounding body at opposing sides of the plurality of directly opposing slits in the first direction.