Spider silk protein film and method for producing the same

A film containing a polypeptide derived from spider silk protein, having a decomposition temperature at 240 to 260 ° C., absorbing ultraviolet light having a light wavelength of 200 to 300 nm, and having a light transmittance of 85% or more at a light wavelength of 400 to 780 nm And is colorless and transparent in the visible light region. In the production method of the present invention, a polypeptide derived from spider silk protein is dissolved in a dimethyl sulfoxide solvent to form a dope solution, and the dope solution is cast-molded on the substrate surface. This provides a spider silk protein film that is easy to form into a film and has good stretchability, and a method for producing the same.