Vehicular antenna device

A vehicular antenna device comprising:

• an antenna element portion including an antenna element;
• an element holder configured to hold the antenna element;
• and
• a case configured to cover at least the antenna element and the element holder, wherein
• the antenna element is sandwiched between the element holder and the case,
• the antenna element includes an opening extending in a second direction perpendicular to a first direction in which the element holder and the case sandwich the antenna element,
• a projection to be inserted into the opening is provided on an inner wall of the case,
• at least a part of a region of the case in contact with the antenna element is located further toward one side in the first direction than a region where the projection is provided, and
• at least a part of a region of the element holder in contact with the antenna element is located further toward an other side in the first direction than the region where the projection is provided.