The object of the present invention is to provide a collagen fiber membrane, which has sufficient strength and can be used as a cell culture substrate, a scaffold material for regenerative medicine (for example, material for tissue engineering of cartilage, bone, ligament, corneal stroma, skin, or liver), an implantation material (for example, wound dressing material, bone grafting material, hemostatic material, anti-adhesive material) or a carrier for drug delivery. The object of the present invention can be solved by a fish-derived collagen fiber membrane, characterized in that (1) a tensile strength is 30MPa or more, (2) a density determined by the gravimetric method, is 0.4g/cm 3 or more, and (3) an average membrane thickness is 1µm to 2mm, and a variation in membrane thickness is plus or minus 30%, relative to the average membrane thickness.
