An inductively coupled plasma processing apparatus includes a processing chamber for accommodating a target substrate to be processed and performing plasma processing thereon, a mounting table provided in the processing chamber for mounting thereon the target substrate, a processing gas supply system for supplying a processing gas into the processing chamber and a gas exhaust system for exhausting the inside of the processing chamber. Further, in the inductively coupled plasma processing apparatus, a high frequency antenna is provided to form an inductive electric field in the processing chamber and a first high frequency power supply is provided to supply a high frequency power to the high frequency antenna. A metal window made of a nonmagnetic and conductive material is formed between the high frequency antenna and the processing chamber while being insulated from a main body which forms the processing chamber.