A film forming apparatus including a film forming chamber which forms a film, a jetting mechanism which jets aerosol containing material particles onto a substrate in the film forming chamber, a measuring chamber communicating with the film forming chamber, a measuring mechanism which measures a thickness of the film in the measuring chamber, a pressure adjusting mechanism which controls an internal pressure of the film forming chamber and the measuring chamber, a conveyor which transports the substrate between the film forming chamber and the measuring chamber, and a blocking section which blocks a communication between the film forming chamber and the measuring chamber. Accordingly, inside of the measuring chamber is maintained clean without being polluted with the aerosol, and the measurement precision can be maintained. In the film forming process, the film thickness can be easily and precisely measured, and fed back to the film forming condition.