Abstract: A steam reflow apparatus includes a heating furnace including a preheating zone, a uniform heating zone, a melting zone and a cooling zone to which superheated steams are respectively supplied. The apparatus further includes a furnace-inlet-side dew condensation prevention zone and a furnace-outlet-side dew condensation prevention zone, to which air or nitrogen gas with 100° C. or higher heated by a heater is supplied, respectively adjacently provided with an upstream side of the preheating zone and a downstream side of the cooling zone. Atmospheric pressures of the furnace-inlet-side dew condensation prevention zone and the furnace-outlet-side dew condensation prevention zone are higher than atmospheric pressures of the preheating zone and the cooling zone.