A plasma generation device, comprising: a plurality of ignition plugs, each having a tip end side formed with a discharge gap and exposed to a corresponding target space; and a high frequency generation device that generates a high frequency wave, wherein: each of said ignition plugs is a high frequency radiator configured to radiate the high frequency wave output from the high frequency generation device to its corresponding target space, plasma being generated by supplying energy of the high frequency wave to that target space from that high frequency radiator, the high frequency generation device includes an oscillator configured to oscillate the high frequency wave, and a plurality of amplifiers configured to amplify the high frequency wave oscillated by the oscillator and output the high frequency wave thus amplified to the corresponding high frequency radiator; from among the oscillator and the amplifiers each amplifier alone is integrated with the corresponding high frequency radiator; a plurality of ignition coils is provided, each coil configured to output a high voltage pulse to a respective one of said ignition plugs, for generating a discharge at the respective discharge gap, the plasma generation device further comprises: a power circuit configured to provide power for the high frequency wave to the high frequency generation device; each amplifier, its corresponding coil and its corresponding ignition plug are integrated in a respective ignition unit; and the oscillator and the power circuit are accommodated in a casing. a plurality of ignition plugs, each having a tip end side formed with a discharge gap and exposed to a corresponding target space; and a high frequency generation device that generates a high frequency wave, wherein: each of said ignition plugs is a high frequency radiator configured to radiate the high frequency wave output from the high frequency generation device to its corresponding target space, plasma being generated by supplying energy of the high frequency wave to that target space from that high frequency radiator, the high frequency generation device includes an oscillator configured to oscillate the high frequency wave, and a plurality of amplifiers configured to amplify the high frequency wave oscillated by the oscillator and output the high frequency wave thus amplified to the corresponding high frequency radiator; from among the oscillator and the amplifiers each amplifier alone is integrated with the corresponding high frequency radiator; a plurality of ignition coils is provided, each coil configured to output a high voltage pulse to a respective one of said ignition plugs, for generating a discharge at the respective discharge gap, the plasma generation device further comprises: a power circuit configured to provide power for the high frequency wave to the high frequency generation device; each amplifier, its corresponding coil and its corresponding ignition plug are integrated in a respective ignition unit; and the oscillator and the power circuit are accommodated in a casing. each of said ignition plugs is a high frequency radiator configured to radiate the high frequency wave output from the high frequency generation device to its corresponding target space, plasma being generated by supplying energy of the high frequency wave to that target space from that high frequency radiator, the high frequency generation device includes an oscillator configured to oscillate the high frequency wave, and a plurality of amplifiers configured to amplify the high frequency wave oscillated by the oscillator and output the high frequency wave thus amplified to the corresponding high frequency radiator; from among the oscillator and the amplifiers each amplifier alone is integrated with the corresponding high frequency radiator; a plurality of ignition coils is provided, each coil configured to output a high voltage pulse to a respective one of said ignition plugs, for generating a discharge at the respective discharge gap, the plasma generation device further comprises: a power circuit configured to provide power for the high frequency wave to the high frequency generation device; each amplifier, its corresponding coil and its corresponding ignition plug are integrated in a respective ignition unit; and the oscillator and the power circuit are accommodated in a casing. a power circuit configured to provide power for the high frequency wave to the high frequency generation device; each amplifier, its corresponding coil and its corresponding ignition plug are integrated in a respective ignition unit; and the oscillator and the power circuit are accommodated in a casing.