A polylactic acid based resin sheet includes a layer formed of a composition (D) containing polylactic acid (A), an ionic surface active agent (B), and a nonionic surface active agent (C), wherein the polylactic acid (A) has a content of 50 mass % or more and 99.5 mass % or less in the entire 100 mass % of the composition (D), and the mass ratio between the ionic surface active agent (B) and the nonionic surface active agent (C) satisfies 2≦(B)/(C)≦20.