A substrate processing apparatus includes a processing chamber in which a substrate is mounted, a gas supply unit that supplies processing gas into the processing chamber, a gas exhaust unit that exhausts atmospheric gas in the processing chamber, first and second electrodes to which high-frequency power is applied to set the processing gas to an active state. Each of the first and second electrodes includes a core wire formed of a metal and plural pipe bodies that are joined to one another through the core wire so as to be bendable, and less thermally deformed than the core wire.