In the vicinity of the blowout outlet 30, direct discharge may occur between the high-voltage electrode 14 and the low-voltage electrode 20 without passing through the dielectric substrate 12. Such discharge damages the high-voltage electrode 14, dielectric substrate 12, and low-voltage electrode 20, thereby causing the materials constituting these components to mix into the plasma as impurities. From a standpoint of discharge efficiency, it is advantageous to mount the high-voltage electrode at the front edge of the blowout outlet. However, this configuration allows the distance between the high-voltage electrode and the low-voltage electrode to become significantly shorter, causing creeping discharge on the dielectric substrate. Once the discharge occurs, it does not form dielectric barrier discharge, but moves on to direct discharge, thus an excessive discharge current flows, thus an excessive discharge current flows, causing damage to the electrodes and eventually damage to the power supply unit. Hence, the plasma generator 10 has the configuration in which the predetermined clearance 15 is provided between the second end of the high-voltage electrode 14 and the surface on which the blowout outlet 30 is formed. This configuration prevents the direct discharge between the high-voltage electrode 14 and the low-voltage electrode 20, and enables the discharge between the high-voltage electrode 14 and the low-voltage electrode 20 through the dielectric substrate 12, thereby preventing damage to the high-voltage electrode 14, dielectric substrate 12, and low-voltage electrode 20. The clearance 15 may preferably be, for example, in the range of 1 to 5 mm.