The present disclosure relates to a thermal plasma processing apparatus capable of efficiently using thermal plasma and securing a reaction time for the thermal decomposition of the processing gas. A Thermal plasma processing apparatus according to an embodiment of the present disclosure includes a torch part in which an arc is generated between a negative electrode and a positive electrode, and in which a processing gas to be thermally decomposed by the arc is injected between the negative electrode and the positive electrode, a power supply part configured to be connected to the negative electrode and the positive electrode and to apply a high voltage between the negative electrode and the positive electrode, and a reaction part configured to communicate with the torch part and to generate turbulence in the processing gas passing through the torch part.