The invention provides a film thickness detection device. The film thickness detection device is used for detecting an evaporation rate of a substrate plate when the substrate plate is evaporated. Thefilm thickness detection device comprises an evaporation source, the film thickness detector, an adjusting part, a gas pipeline and a heating part, wherein the evaporation source is provided with a nozzle; the nozzle, the gas pipeline, the adjusting part and the film thickness detector are arranged at a first direction in sequence; the nozzle communicates with a material feeding port of the gas pipeline, the adjusting part can rotate around a fixed shaft, and a plurality of through holes which are arranged at intervals are formed in the adjusting part; and the heating part is arranged aroundthe periphery of the gas pipeline, and then a vacuum evaporated material evaporated from the nozzle is kept in a gas state when passes through the gas pipeline in the first direction, and is vacuum evaporated on the film thickness detector through the through holes. According to the film thickness detection device and the vacuum evaporating machine, the technical problem that the production efficiency is low due to the fact that blockage of the through holes caused by the vacuum evaporated material is solved.