Abstract: A high-performance and compact antenna apparatus is provided which is capable of obtaining a high antenna gain, less susceptible to wind and the like, and advantageously useful as mounted on vehicles or the like. The antenna apparatus includes: a transmitting antenna section 2 having at least one planar antenna element for transmitting a radio wave to a satellite; a receiving antenna section 3 having at least one planar antenna element for receiving a radio wave from the satellite, the transmitting antenna section 2 and the receiving antenna section 3 being positioned to orient to a predetermined satellite and arranged stepwise with a predetermined spacing therebetween.