A parking assistance system comprising: a first overhead view video generation section that generates, based on camera videos shot by a plurality of cameras mounted to a vehicle, a first overhead view video virtually overlooking, from above the vehicle, conditions surrounding the vehicle with the vehicle located at a center therein; a parking target position detection section that detects a parking target position for parking the vehicle from the first overhead view video; a viewpoint position determination section that determines a viewpoint position based on a positional relationship between the parking target position detected by the parking target position detection section and a vehicle position in the first overhead view video; a rotation amount determination section that determines a rotation amount in the first overhead view video based on the positional relationship between the parking target position and vehicle position in the first overhead view video; a viewpoint conversion table recording section that records therein a plurality of viewpoint conversion tables for moving a center position of the first overhead view video to the viewpoint position and rotating the first overhead view video with respect to the viewpoint position as a rotation center by the rotation amount; and a second overhead view video generation section that extracts, from the view point conversion tables recorded in the view point conversion table recording section, a viewpoint conversion table for moving a center position of the first overhead view video to the viewpoint position determined by the viewpoint position determination section and rotating the first overhead view video by the rotation amount determined by the rotation amount determination section and applies video conversion processing to the first overhead view video based on the extracted viewpoint conversion table to generate a second overhead view video and outputs the second overhead view video to a display section, wherein the rotation amount determination section determines, as the rotation amount, a rotation angle of the first overhead view video such that the parking target position is located below the vehicle position. a first overhead view video generation section that generates, based on camera videos shot by a plurality of cameras mounted to a vehicle, a first overhead view video virtually overlooking, from above the vehicle, conditions surrounding the vehicle with the vehicle located at a center therein; a parking target position detection section that detects a parking target position for parking the vehicle from the first overhead view video; a viewpoint position determination section that determines a viewpoint position based on a positional relationship between the parking target position detected by the parking target position detection section and a vehicle position in the first overhead view video; a rotation amount determination section that determines a rotation amount in the first overhead view video based on the positional relationship between the parking target position and vehicle position in the first overhead view video; a viewpoint conversion table recording section that records therein a plurality of viewpoint conversion tables for moving a center position of the first overhead view video to the viewpoint position and rotating the first overhead view video with respect to the viewpoint position as a rotation center by the rotation amount; and a second overhead view video generation section that extracts, from the view point conversion tables recorded in the view point conversion table recording section, a viewpoint conversion table for moving a center position of the first overhead view video to the viewpoint position determined by the viewpoint position determination section and rotating the first overhead view video by the rotation amount determined by the rotation amount determination section and applies video conversion processing to the first overhead view video based on the extracted viewpoint conversion table to generate a second overhead view video and outputs the second overhead view video to a display section,