PURPOSE: The titled fiber suitable for use as a binding fiber for hygienic materials that is made by subjecting a copolyester of a specific composition to melt spinning, thus having a specific intrinsic viscotiy, filament denier, satisfactory crimping, strength and elongation and showing good processability and high adhesion.

CONSTITUTION: A copolyester consisting of the acid component containing isopthalic and terphtalic acids at 30/70W60/40 molar ratio and/or their ester-forming derivative and of the glycol component is melted, extruded through a nozzle with orifices of modified cross section, solidified by cooling, passed through a hot chimney, then drawn to produce the objective three-dimensionally crimped fiber of 0.5W0.6 intrinsic viscosity, 4 or more/inch crimping number, higher than 5% crimp index, more than 0.8g/d denier tenacity, more than 10% denier elongation and 1W15 denier filament fineness.