A cover member of the present invention is a cover member to be placed on a face of an object to prevent passage of a foreign matter through an opening of the face, the cover member including: a protective membrane having a shape configured to cover the opening when the cover member is placed on the face; and a first substrate layer joined to one of principal surfaces of the protective membrane. The first substrate layer has a laminated structure including at least two substrate films, and is positioned between the protective membrane and the face when the cover member is placed on the face. The at least two substrate films include a non-foam film and a foam film. The cover member of the present invention is suitable for improving the peelability from a member supply sheet.