Provided is a low-profile antenna device that allows the height of an antenna to be further reduced. The low-profile antenna device comprises a base section, a helical antenna section, and a top load section. The helical antenna section is wound along an oblique axial direction starting from the base section. The conductive top load section, which is electrically connected to the tip of the helical antenna section, has a top section that is provided on the opposite side to a vehicle, to which the antenna device is fixed, and side sections that are provided on the vehicle side in oblique directions from the top section such that no part of the helical antenna section is placed between the top load section and the vehicle in the direction of a perpendicular line formed therebetween.