1. A panoramic image generation method which generates a surrounding 360-degree panoramic image data centering around a photographing point using a plurality of photographed image data, wherein, a same subject is included in each of first photographed image data which is time-serially obtained and last photographed image data which is time-serially obtained among the plurality of the photographed image data, the panoramic image generation method comprising: a first step of combining the plurality of the photographed image data to generate a surrounding 360-degree or more panoramic image data centering around the photographing point; a second step of performing at least one of a first process in which any of the subject of a starting end and the subject of a terminal end is deformed with respect to the subject included in each of the starting end and the terminal end of the surrounding 360-degree or more panoramic image data, to match a size and a posture of the subject of the starting end with those of the subject of the terminal end, and a second process in which any of the subject of the starting end and the subject of the terminal end is deformed with respect to the subject included in each of the starting end and terminal end of the surrounding 360-degree or more panoramic image data, to match positions in a short length direction of the surrounding 360-degree or more panoramic image data; and a third step of overlapping the subjects respectively included in the starting end and the terminal end of the surrounding 360-degree or more panoramic image data with each other, to generate the surrounding 360-degree panoramic image data, after the second step.