To reduce the cost of a power generation system and pollution by employing a plasma melting furnace as a thermal energy source.

A pipe (2) having a proper material and a shape is laid along a wall surface of a plasma melting furnace (1) having a proper material and a shape, and water (3) is heated with heat (4) in the plasma melting furnace (1) to produce high temperature high pressure water vapor (5), with which water vapor (5) a turbine (6) is rotated to convert it to mechanical energy, rotational force of which turbine is transmitted to a power generator (7) to generate electric energy. The high temperature high pressure water vapor that has rotated the turbine (6) is converted to water with a condenser (9) providing cooling water (8).