A film forming apparatus includes a reactor chamber, a first electrode provided in the reactor
chamber and receiving electrical power, a second electrode provided in the reactor chamber
and facing the first electrode, a gas supply inlet for supplying material gas to a space
between the first and second electrodes, and a gas exhaust outlet for discharging the
material gas. Insulating material is not exposed to a flow path for the material gas in the
reactor chamber.

In one embodiment, a film forming apparatus includes a chamber configured to load a
substrate, a stage configured to support the substrate, and a gas supplier configured to
supply a gas into the chamber to form a film on the substrate. The device further includes a
first detector configured to detect a first value that varies depending on at least pressure of a
first portion above the stage in the chamber, and a controller configured to control a process
of forming the film on the substrate based on the first value.