PURPOSE: To improve working efficiency and to stabilize a forging quality by forming the gaseous atm. mixing a lubricant powder into an inert gas and executing forging under the atm. thereof.

CONSTITUTION: The body 2 to be worked is set inside a chamber 1 and the chamber inside is evacuated by a vacuum pump 9. The inert gas 5 mixing a lubricant is then sealed inside the chamber and held with the temp. up to the specified pressure. After heating the body 2 to be worked in that state by a high frequency coil heater 6 up to the forging temp. the forging is executed. The need for feeding the lubricant separately by a nozzle, etc., is thus eliminated, the lubricant is uniformly fed to the body 2 to be worked and the post treatment of removing an oxidized film is also made unnecessary. Consequently the working efficiency is improved and forging quality is stabilized.