An antenna apparatus which exhibits excellent mechanical strength and which is protected from heat and moisture, and also which is mountable on a printed wiring board with the provision of a clearance between the apparatus and the board, free from deformation caused by a warp of the board. The antenna apparatus has a rectangular-prism shaped substrate. A feeding terminal and a fixing terminal are disposed at the respective end surfaces in the longitudinal direction of the substrate. Metal strips serving as support terminals are soldered at the respective first ends to the feeding terminal and the fixing terminal, respectively. A coating material formed of a non-metallic material, such as glass, resin or the like, is applied to the surface of the substrate by way of coating, dipping or other method. A coating layer is thus formed on the substrate in a state in which the respective second ends of the metal strips project from the substrate.