The invention provides a film thickness monitor and a thermal evaporator. The film thickness monitor comprises a housing, a rotating disk disposed in the housing, a plurality of film thickness monitoring sensors which are disposed in the housing and are fixed to the rotating disk, a window disposed in the housing, and a fan disposed in the window. The rotating disk rotates, driving the plurality of film thickness monitoring sensors to pass the window in order. With the installation of the fan in the window of the housing, the organic micromolecule material volatilized to the window during theprocess of evaporation will be reduced, and the film thickness deposited on the surface of the film thickness monitoring sensor can be decreased, the service lifetime of the film thickness monitoringsensor will be prolonged, and the opening times of the cavity body of the thermal evaporator will be reduced, and the operation ratio and production power of the thermal evaporator will be improved. The thermal evaporator is advantageous in that with the installation of the film thickness monitor, the opening times of the cavity body of the thermal evaporator will be reduced, and the operation ratio and production power of the thermal evaporator will be improved.