Substrate processing apparatus, substrate processing method, and storage medium

The invention provides a substrate processing apparatus, a substrate processing method, and a storage medium, which can restrain film thickness deviation of a film formed on a substrate. The substrate processing apparatus includes: a tube member forming a cylindrical processing chamber; a plurality of partition members formed on the outer peripheral surface side of the pipe member so as to be arranged in the circumferential direction and partitioning supply chambers communicating with the processing chamber through the supply holes; one or more gas nozzles are disposed in each of the plurality of supply chambers, each gas nozzle having an injection hole formed in a side surface thereof for injecting the process gas flowing therethrough into the process chamber through the supply hole, and extending in the axial direction; and a plurality of gas supply pipes for communicating the plurality of gas nozzles with the corresponding gas supply sources, respectively. The supply chamber includes a first nozzle chamber