A manufacturing method of an amorphous soft magnetic core using a Fe-based amorphous metallic powder includes size-sorting an amorphous metallic powder obtained by pulverizing an amorphous ribbon prepared by a rapid solidification process (RSP) and then using the amorphous metallic powder having a particle size distribution so as to comprise 10 to 85 wt. % of powder having a particle size of 75 to 100 μm, 10 to 70 wt. % of powder having a particle size of 50 to 75 μm, and 5 to 20 wt. % of powder having a particle size of 5 to 50 μm to manufacture an amorphous soft magnetic core with excellent high-current DC bias characteristic and good core loss characteristic.