In a device for generating a vapor for a CVD or PVD apparatus, at least two thermal transfer bodies are arranged successively in the direction of flow of a carrier gas. The device also includes an inlet pipe for feeding an aerosol to one of the thermal transfer bodies for vaporization of the aerosol by bringing the aerosol particles into contact with thermal transfer surfaces of the thermal transfer body. At least one of the thermal transfer bodies has an opening for an inlet pipe that has a first flow channel for feeding the aerosol in and a second flow channel for feeding a carrier gas in. Gas passage openings are provided through which the carrier gas flows out of the second flow channel into the first flow channel. The second flow channel is sealed in the area of the mouth of the inlet pipe.