A digital zoom rate of two-dimensional images zoomed by a digital zoom unit is obtained. When the obtained digital zoom rate is larger than 100%, at least one of the digitally zoomed two-dimensional images is modified based on an enlarged amount of parallax to provide an amount of parallax between the digitally zoomed two-dimensional images equal to the enlarged amount of parallax. The enlarged amount of parallax is obtained by enlarging, at a moderated digital zoom rate, an amount of parallax between the two-dimensional images before being digitally zoomed, and the moderated digital zoom rate is obtained by moderating the digital zoom rate at a moderation rate, where the moderation rate increases as the zoom rate increases. Then, a display unit is caused to carry out three-dimensional display based on the modified two-dimensional images.