a filament having excellent incision resistance includes as a primary component a polyethylene filament having a weight - average molecular weight of 300 , 000 or less and a ratio of a weight - average molecular weight to a number - average molecular weight of 4 . 0 or less as determined in the state of a filament as well as a modulus of 500 cn / dtex or more . this filament is useful to produce a fabric excellent in incision resistance , a fibrous material for reinforcing mortar or concrete , and a rope , each of which comprises the filament . the filament can be produced by drawing a non - drawn polyolefin filament which comprises a polyethylene having a weight - average molecular weight of 60 , 000 - 600 , 000 , a ratio of a weight - average molecular weight to a number - average molecular weight of 4 . 5 or less , and a rate of birefringence of 0 . 008 or more , at a temperature not higher than the α - relaxation temperature of the non - drawn filament .