To obtain a polyolefin-based fiber paper, excellent in dispersibility of the fibers in the paper-making process, very little foamed during the dispersion process, good in texture, high in adhesive power even in boiling water, highly resistant to breaking while in service, and particularly useful for heat seal bags for boiling sterilization, disinfection and cleaning for. e.g. medical purposes.

This polyolefin-based fiber paper contains 5 to 100 wt.% of a core-sheath type composite fiber, with a modified polypropylene copolymerized with 1 to 8 wt.% of ethylene and having a boiling point of 135°C or more as the sheath and propylene as the core, and 0.03 to 2 wt.% of a polyether amide- based compound added, and has a heat seal dry peel strength of 100 g/cm or more and heat seal peel strength in boiling water of 50 g/cm or more.