An object of the present invention is to provide a simple measure which can suppress freshness deterioration of a myoglobin-containing food. The present invention relates to a myoglobin-containing food freshness deterioration suppressing material for suppressing freshness deterioration of a myoglobin-containing food, comprising: a substrate comprising a polymer; and an antioxidant with which at least a part of the surface of the substrate is covered, and/or an antioxidant supported in a layer forming at least a part of the surface of the substrate; wherein 0.01 g/m2 or more and 20 g/m2 or less of the antioxidant is included relative to the area of the part in which the antioxidant is present, of the surface of the substrate.