Provided is a small electronic component (10) excellent in magnetic powder escape prevention ability, external electrode bonding property, withstand voltage characteristics, antirust ability, heat resistance, strength after heat curing, and moldability, the small electronic component (10) including: a magnetic core (100) including at least a columnar core part (110); a winding coil (200) arranged so as to surround an outer peripheral surface side of the columnar core part (110) and formed by winding a winding wire (210); and a magnetic cover part (300) formed so as to cover at least part of the magnetic core and the winding coil while following at least part of shapes of the magnetic core and the winding coil through use of a magnetic material containing a mixture of a phosphoric acid ester-based surfactant, magnetic powder, and a resin, an electronic circuit board using the small electronic component, and a method of manufacturing a small electronic component.