To provide an artificial pericardial membrane sheet in which a surface (portion) that is ion bombarded and a surface (portion) that is not ion bombarded can be distinguished. Provided are: an artificial pericardial membrane sheet in which [Delta]b is 2 to 11, where [Delta]b is the difference between a b1 value, which is a b value of a roughened portion 3, and a b2 value, which is a b value of a second surface 7； and a method for manufacturing the artificial pericardial membrane sheet that includes a roughening step of roughening all or a part of a first surface 5 of a sheet that comprises polytetrafluoroethylene by ion bombardment to form a roughened portion 5, wherein the ion bombardment is continuously performed under a vacuum of 10<；SP>；-7<；/SP>； to 10<；SP>；-1<；/SP>； atm.[課題]提供一種人工心包膜薄片，能區別施予離子撞擊的面（部分）與未施予離子撞擊的面（部分）。[解決手段]一種人工心包膜薄片，粗面化部3的b值為b1值，第2面7的b值為b2值，令b1值與b2值的差為Δb時，Δb為2以上11以下；以及一種人工心包膜薄片的製造方法，包含：粗面化步驟，將含有聚四氟乙烯的薄片的第1面5的全部或一部分，藉由離子撞擊做粗面化處理而形成粗面化部5；其中，離子撞擊是在10-7大氣壓以上10-1大氣壓以下的真空度中連續地進行。
