Structural relaxation in amorphous 1,2-dichloroethane (DCE) samples prepared by vapor deposition on cold substrates were studied by Raman scattering. The gauche and trans molecules of DCE were found to coexist in amorphous states immediately after the deposition, and structural relaxation occurred with temperature elevation before crystallization. Mole fraction of the gauche isomer increased during this relaxation process, although trans is the stable isomer in gaseous and crystalline states. At the final amorphous stage immediately before crystallization, the gauche mole fraction was close to the mole fraction of the supercooled liquid state. It was also found that trans molecules located at positions with lower density were more easily transformed into the gauche conformation, while the distribution of the local structure around the resultant gauche molecules remained almost unchanged during the structural relaxation. Such behaviors of amorphous DCE are discussed from the viewpoint of the characteristic molecular structure of DCE.