In the plasma generator 10, the groove 22 is formed in the low-voltage electrode 20, and the portion enclosed by the groove 22 and the second surface 13b of the dielectric substrate 12 forms the gas channel 25. The dielectric substrate 12 itself has a flat plate without grooves or holes. In general, processing (in the first embodiment, forming the groove 22) the low-voltage electrode 20, which is made of metal, is easier than processing the dielectric substrate, which is made of ceramic or other material. Hence, this configuration enables the plasma generator 10 to be readily manufactured. Since the dielectric substrate 12 is flat, the plasma generator 10 can be made thin. Therefore, this configuration is capable of increasing the amount of plasma generated per unit power, enabling efficient plasma generation.

In the first embodiment, the width of the groove 22 (gas channel 25) is uniform from the first end to the second end; however, the present invention is not limited to this example. The width of the groove (gas channel) is not necessarily to be uniform from the first end to the second end. For example, the width of the groove (gas channel) may be configured to become narrower from the first end to the second end. The width of the groove (gas channel) may also be configured to become wider from the first end to the second end.