The structures of a gelatin gel in various phases were examined using wide angle X-ray diffraction (WAXD), differential scanning calorimeter (DSC), and spectroscopic measurements. The structure of the gelatin gel in a dry film was analyzed using WAXD. In order to examine the thermal history effect on the gelatin gel forming, the gelation of gelatine solutions was carried out at various temperatures, and then the gelatin films were prepared using dry air. The gelatin gel junction was formed by the assembly of the collagen-like triple helices that are reformed from the gelatin sol state. The quantity of the helical fraction and its assembled form in the film decreased with an increase in the gelation temperature. However, the gel junctions tightly assembled with an increase in the gelation temperature and indicated higher melting temperature. The structures of the gelatin gels prepared from a gelatin sol by rapid or slow cooling were estimated by the DSC and jelly strength measurements. When a gelatin gel was prepared by rapid cooling, large quantities of small size gel junctions were produced, and a minute gel network was formed. On the other hand, large sizes gel junctions showing higher melting temperatures were produced in the gelatin gel by the slow cooling of the gelatin sol. The structure of the gelatin gel, which contains both physical and chemical crosslinking, was examined in an aqueous phase using both circular dichroism (CD) and fluorescence depolarization methods. The regeneration ratio of the triple-helical structure, which was determined by CD, monotonously increased with an increase in the amount of chemical crosslinks introduced into the collagen molecules. On the other hand, the quantity of the physical junction reformed around the fluorescent chemical crosslink was examined using the fluorescence depolarization method. The quantity of the triple helix around the crosslink increased within a range in which the proportion of artificially introduced crosslinks was below 10% and decreased above the 10% range.