1. A three-dimensional image output device characterized by comprising: a viewpoint image acquiring device for acquiring a plurality of viewpoint images obtained by photographing a same subject from a plurality of viewpoints; a parallax information acquiring device for acquiring parallax amounts in a plurality of sets of feature points at which features correspond to one another from the acquired plurality of viewpoint images; a parallax amount adjusting device for adjusting the acquired parallax amount in each of the feature points, and performing adjustment of assigning different weights to the parallax amounts in accordance with values of the parallax amounts; a parallax image generating device for generating a parallax image corresponding to the parallax amount of each of the feature points after the adjustment; and a parallax image output device for outputting a plurality of parallax images including the generated parallax image, wherein the parallax amount adjusting device includes a plurality of conversion tables, each of which represents an input-output relationship of a parallax amount and a parallax adjustment parameter for adjusting the parallax amount, the input-output relationships of the plurality of conversion tables being different from each other, and the parallax amount adjusting device selects one of the conversion tables depending on a size of a display device used for stereoscopic display or a visual distance from among the plurality of conversion tables, reads out a parallax adjustment parameter corresponding to the acquired parallax amount of each of the feature points from the selected conversion table and performs adjustment of assigning different weights to the parallax amounts in accordance with the read parallax adjustment parameters.