A vapor contact-type heating device which achieves a high-quality heat treatment is provided by increasing the mixing efficiency of vapor and supplying vapor at a relatively low pressure. By providing a pressurizing duct 45 of the liquid within a vapor mixing pump 4 as a fluid transfer means and providing a vapor supply port 46 on a casing 43 in such a manner that the vapor supply port 46 opens to this pressurizing duct 45, a vapor supply region 47 is formed in the pressurizing duct 45.