The present invention minimizes any strength reduction or tissue degeneration from before treatment even when a drying treatment or sterilization treatment is carried out for tissue comprising bio derived components and the like. More specifically biological tissue is immersed in a trehalose solution and shaken thereby impregnating the biological tissue with the trehalose solution. The trehalose solution used herein is one obtained by dissolving trehalose in a phosphate buffered physiological saline the concentration of trehalose preferably being in the range of 20 35 wt%. Thereafter a drying treatment for the biological tissue is carried out to remove moisture in the biological tissue and a sterilization treatment for the tissue by ethylene oxide gas sterilization is carried out.
