PURPOSE: To provide the method for producing the polyolefin net-like fiber excellent in strength and openability and suitable for the production of flush spun non-woven fabric sheets by using a non-flammable hydrocarbon halide extremely reduced in the ozone layer-destroying function.

CONSTITUTION: The method for producing the fibrillated polyolefin three- dimensional not-like fiber by passing a high temperature and high pressure polyolefin solution through a pressure-reducing orifice, a pressure-reducing chamber and a spinneret, and subsequently releasing the solution into an ordinary temperature and ordinary pressure area is characterized by employing a solvent mixture comprising trichloroethylene or perchloroethylene and one kind or more of cosolvents selected from dodecafluoropentane, decafluoropentane, tetradecafluorohexane, 1,1-dichloro-2,2,3,3,3- pentafluoropropane, and 1,3-dichloro-1,2,2,3,3-pentafluoropropane and controlling the rate of the polyolefin in the polyolefin solution to 5-25wt.%.