PURPOSE: To maintain stabilized permeability and prevent filled powder from leaking and also from distributing unevenly by using a non-woven cloth constituted of thermoplastic resin fibers having different melting points and a permeable paper, forming recesses and projections by the non-woven cloth, making the recessed sections in the form of a film and making the recessed sections bonded with the paper.

CONSTITUTION: A sheet material 1 is formed by bonding only a non-woven cloth 2 constituted of thermoplastic resin fibers having different melting points and a permeable paper 3. The non-woven cloth 2 in bonding sections 6 are made in the form of film, and permeability is maintained through the sheet material 1 in the sections other than the bonding sections. Sections other than the bonding sections of the non-woven cloth 2 form recessed sections 4. In order to improve the bonding properties of the paper 3 and the non-woven cloth 2, the sheet material 1 should preferably contain olefin and the like, and the fibers of the non- woven cloth 2 are preferably a non-woven cloth of 20-100g/m2 weight per unit area, in case polyester is used for a core and polyethylene is used as a sheath for the fibers of the non- woven cloth 2. 30-50g/m2 weight per unit area is used preferably from the viewpoints of heat sealing strength, feeling in hand touch of a bag and the cost of the bag after filling the powder 8.