A plasma processing apparatus includes a stage for supporting a target object in a chamber defined by a chamber body. The stage includes a lower electrode, an electrostatic chuck provided on the lower electrode, heaters provided in the electrostatic chuck, and terminals electrically connected to the heaters. A conductor pipe electrically connects a high frequency power supply and the lower electrode and extends from the lower electrode to the outside of the chamber body. Power supply lines supply power from a heater controller to the heaters. Filters partially forming the power supply lines prevent the inflow of high frequency power from the heaters to the heater controller. The power supply lines include wirings which respectively connect the terminals and the filters and extend to the outside of the chamber body through an inner bore of the conductor pipe.