The sheets prepared by the extrusion of the melt of poly(butylene succinate) were treated with inorganic gas plasmas. Bionolle, the commercially available polyester, was also used, and the treatment effects were compared. Plasma susceptibility by the continuous plasma of 13.56 MHz and by pulsed plasmas was evaluated by the weight lass rates by etching. Advancing and receding contact angles of water (theta(a), theta(r)) on the plasma-treated sheets were obtained by the Wilhelmy method. Decay of hydrophilicity was considerable in theta(a), but theta(r), was less changed. The biodegradation was examined by the preliminary soil-burial tests. The polymer sheets were biologically degraded, and the characteristic morphology appeared on the surface according to the SEM observation.