Abstract: A plasma process apparatus performing an even plasma processing over the entire surface of a substrate, without accompanying thermal damage, and method of the plasma processing. In a process room 2, where a semiconductor wafer 4 is placed on a lower electrode 3 for processing with plasma, the semiconductor wafer 4 which has been fixed on a resin sheet 4a whose thermal expansion coefficient is greater than that of the semiconductor wafer 4 is pressed at the circumference edge by a substrate holding device 5 onto the surface of lower electrode 3. In such a setup, central portion of the semiconductor wafer can also be pressed onto the lower electrode 3 via the resin sheet 4a. Thus, there will be no gap between the surface of lower electrode 3 and the substrate, which contributes to eliminate thermal damages due to abnormally high temperature and to avoid a local discharge.