The present invention provides a film forming apparatus capable of enabling source gases to isotropically flow and reducing the size of its chamber. When a susceptor with substrate holders containing substrates moves downward, the substrate holders are combined with a clutch mechanism. When a driving motor runs, a rotating shaft conformably rotates. The rotation is transmitted to a central gear through the clutch mechanism so as to rotate the central gear. Thus, the substrate holder whose peripheral surface is engaged with the center gear accordingly rotates so as to rotate the substrates. When the driving motor runs, a revolving shaft conformably rotates. The rotation is transmitted to the susceptor through a revolving clutch mechanism so as to rotate the susceptor and revolve the substrates. Process gases are fed via an inlet so that expected films are formed on the substrates when the substrates are at rotation and revolution statuses.