In an active gas generating apparatus, a power feeder is provided above metal electrodes in an integrated high-voltage electrode unit. When seen in plan view, the power feeder has a shape that entirely covers the metal electrodes in the integrated high-voltage electrode unit. Each of power feeding units is provided below the metal electrodes in an integrated ground electrode unit. When seen in plan view, each of the power feeding units has a shape that entirely covers the metal electrodes of the integrated ground electrode unit.