The silicone resin is preferably coated on both opposing surfaces of the sheets to obtain better effects.In order to manufacture a medical bag as described above, a pair of elongated sheets 11 and 12 are prepared as shown in FIGS. 1A and 1B. These elongated sheets 11 and 12 are made of a thermoplastic resin (e.g., polyvinyl chloride, orolefin-based resin such as polyethylene) and an ethylene-vinyl