To provide a vapor generating device, constituted so as to be capable of reducing a cost, necessary for the installation of the steam generating device, without spoiling the quality of the device.

A vapor generating device is equipped with a plurality of dust burners 4, which are arranged up-and-down, while an oil lance is arranged in the dust burners 4 respectively. Further, the vapor generating device is equipped with one or a plurality of combustion gas passages 3 to conduct combustion gas to flow through the same while an air preheater 6, retained by a trestle 12, is connected to the combustion gas passage 3. A joint 9 at the side of outlet port of combustion gas for the air preheater 6 is connected to an electric filter 17 through a distributor pipeline 20 while the electric filter 17 is equipped with a filter casing 17 and one or a plurality of inlet port side ducts 18. The distributor pipeline 20 is arranged below the joint 9 at the side of outlet port of combustion gas for the air preheater under vertical condition while the air preheater 6 is installed on the installation area of the oil lance for the dust burners 4.