There is provided a technique that includes a process chamber configured to process a substrate; a gas supplier configured to supply a gas into the process chamber; a first plasma electrode unit including a first reference electrode applied with a reference potential and at least one selected from the group of a first application electrode and a second application electrode applied with high-frequency power, the first plasma electrode unit configured to plasma-excite the gas; and a second plasma electrode unit including a second reference electrode applied with a reference potential and a third application electrode applied with high-frequency power, the third application electrode having a length different from a length of the first application electrode or the second application electrode, and the second plasma electrode unit configured to plasma-excite the gas.