An antenna unit includes an antenna module that receives radio waves sent from a satellite or earth, a cover member that has enough inner space to house the antenna module and has an opened bottom surface, and a bottom plate that closes the opened bottom surface of the cover member, and the antenna unit is attached to a resin-made attachment part. A metal sheet is provided on a back surface side of the resin-made attachment part, and the antenna unit is adhesive bonded and fixed on a surface side of the resin-made attachment part correspondingly to an arrangement position of the metal sheet.