A parking assistance apparatus makes it easy for a driver to grasp a relative positional relation between a vehicle and a target parking position and makes it possible to park the vehicle at the target parking position in a parking space with accuracy.An image of a mark M in a parking space S is taken by a vehicle-side camera 7. A relative position calculation portion 8 calculates a relative positional relation between the vehicle and a target parking position T based on the taken image of the mark M. A backward locus calculation portion 9 calculates an expected locus when the vehicle moves based on the relative positional relation and based on a steering angle detected by a steering angle sensor 15. An image of the parking space S is taken by a parking-space-side camera 3 and transmitted to a vehicle-side apparatus 1. An image composition portion 12 composes the image of the parking space S from the parking-space-side camera 3 and the expected locus calculated by the backward locus calculation portion 9. The composed image is displayed on the monitor 14 located in the vicinity of a drivers seat of the vehicle.