the frequency f new is generated and amplified up to a given output by an rf amplifier portion 44 electric power is fed to the feeding point 12 via a coaxial cable 45 the static capacitance c_new is sent to the variable capacitive device control portion 33 via a signal line 46 the value of the variable capacitive device 31 is appropriately adjusted as described previously in the techniques set forth in jp a 2000 49000 and jp a 2003 37101 it has been difficult to cope with various conditions in which the electric discharge pressure or electric discharge power is varied as shown in fig8 in contrast in the plasma processing apparatus according to the present invention it is possible to cope with a wide range of conditions by appropriately adjusting the static capacitance of the variable capacitive device 31 fig2 a shows the results of a reflected wave map obtained using the present invention under the same electric discharge conditions as in fig8 fig2 b shows a map of capacitance values of the variable capacitive device 31 at this time as can be seen from fig2 a reflected wave pr 0 w under all the conditions furthermore it can be seen from fig2 b that it is appropriate to use greater static capacitances under conditions of 533 pa and 1000 w where the reflected wave was large in fig8 and under conditions of 100 pa and 4500 w fig2 b shows only the results using o 2 gas it has been confirmed that even when other gas systems i e mixture gas systems such as h 2 n 2 system h 2 he system and n 2 cf 4 system are used reflected.