A plasma doping apparatus implants an impurity element into a surface of a processing target object W by using plasma. The apparatus includes a high frequency power supply 72 configured to supply a high frequency bias power to a mounting table 34 installed within a processing chamber 32; a gas feed unit 96 configured to supply a doping gas containing an impurity element into the processing chamber 32; and a plasma generation unit 78 configured to generate the plasma within the processing chamber 32. In accordance with this apparatus, a portion doped with the impurity element can be made very thin, and the impurity element can be rapidly doped in a high concentration.