There is provided a substrate processing apparatus for performing film formation by supplying a processing gas to a substrate, including: a rotary table provided in a processing container; a mounting stand provided to mount the substrate and configured to be revolved by rotating the rotary table; a processing gas supply part configured to supply a processing gas to a region through which the mounting stand passes by the rotation of the rotary table; a rotation shaft rotatably provided in a portion rotating together with the rotary table and configured to support the mounting stand; a driven gear provided on the rotation shaft; a driving gear provided along an entire circumference of a revolution trajectory of the driven gear to face the revolution trajectory of the driven gear and configured to constitute a magnetic gear mechanism with the driven gear; and a rotating mechanism configured to rotate the driving gear.