A fin-shaped antenna apparatus for vehicle ratio application is electrically connected to a wireless receiver circuit and receives a radio signal. The fin-shaped antenna apparatus includes a fin-shaped cover, an AM antenna, a signal amplifier circuit board, an FM resonance circuit on the signal amplifier circuit board and a metal base. The AM antenna is separated with the FM resonance circuit. The FM resonance circuit comprises a plurality of inductors to form a resonance circuit and is connected to a metal base for enhancing the signal reception thereof. Therefore the signal quality for vehicle ratio application is enhanced.