A plasma generation device (10, 110) comprising: a reaction chamber; multiple electrodes (24, 26) arranged in the reaction chamber; an electric power supply device configured to supply electric power to the multiple electrodes (24, 26) arranged in the reaction chamber; a processing gas supply device configured to supply a processing gas to the reaction chamber; and a control device configured to control operation of the electric power supply device and the processing gas supply device, wherein the control device is configured to control operation of the processing gas supply device and the electric power supply device in either of a first operation mode in which, when a stop signal is received while electric power is being supplied to the electrodes (24, 26) in a state with the processing gas being supplied to the reaction chamber, supply of electric power to the electrodes (24, 26) is stopped and supply of the processing gas to the reaction chamber is stopped, and a second operation mode in which supply of electric power to the electrodes (24, 26) is stopped, but the processing gas continues to be supplied to the reaction chamber, characterized in that the plasma generation device (10, 110) is provided with a heated gas ejecting device including a heating-use gas supply device configured to supply a heating-use gas, and a heater configured to heat gas supplied by the heating-use gas supply device, and configured to eject heated gas that was heated by the heater towards a processing body that is a target for application by the plasma generated by the plasma generation device (10, 110), and the control device is configured to control operation of the electric power supply device, the processing gas supply device, and the heated gas ejecting device so as to, when the stop signal is received while electric power is being supplied to the electrodes (24, 26) and the heated gas is being ejected by the heated gas ejecting device in a state with the processing gas being supplied to the reaction chamber, stop the heating of the gas by the heater at a time at which the stop signal was received, and, in the first operation mode, stop supply of the gas by the heating-use gas supply device after a fourth set time has elapsed from the time at which the stop signal was received, and, in the second operation mode, stop supply of gas by the heating-use gas supply device after a fifth set time that is longer than the fourth set time has elapsed. a reaction chamber; multiple electrodes (24, 26) arranged in the reaction chamber; an electric power supply device configured to supply electric power to the multiple electrodes (24, 26) arranged in the reaction chamber; a processing gas supply device configured to supply a processing gas to the reaction chamber; and a control device configured to control operation of the electric power supply device and the processing gas supply device, wherein the control device is configured to control operation of the processing gas supply device and the electric power supply device in either of a first operation mode in which, when a stop signal is received while electric power is being supplied to the electrodes (24, 26) in a state with the processing gas being supplied to the reaction chamber, supply of electric power to the electrodes (24, 26) is stopped and supply of the processing gas to the reaction chamber is stopped, and a second operation mode in which supply of electric power to the electrodes (24, 26) is stopped, but the processing gas continues to be supplied to the reaction chamber, characterized in that the plasma generation device (10, 110) is provided with a heated gas ejecting device including a heating-use gas supply device configured to supply a heating-use gas, and a heater configured to heat gas supplied by the heating-use gas supply device, and configured to eject heated gas that was heated by the heater towards a processing body that is a target for application by the plasma generated by the plasma generation device (10, 110), and the control device is configured to control operation of the electric power supply device, the processing gas supply device, and the heated gas ejecting device so as to, when the stop signal is received while electric power is being supplied to the electrodes (24, 26) and the heated gas is being ejected by the heated gas ejecting device in a state with the processing gas being supplied to the reaction chamber, stop the heating of the gas by the heater at a time at which the stop signal was received, and, in the first operation mode, stop supply of the gas by the heating-use gas supply device after a fourth set time has elapsed from the time at which the stop signal was received, and, in the second operation mode, stop supply of gas by the heating-use gas supply device after a fifth set time that is longer than the fourth set time has elapsed.