Disclosed is a reflow furnace wherein, in order to prevent a vaporized flux from being adhered and solidified on motor rotating shafts for rotating fans disposed in a preheating zone, a main heating zone, and a cooling zone, the vaporized flux is efficiently and reliably recovered in a liquefied state wherein the flux has a fluidity higher than the fluidity with which the flux is solidified. A drain section (20) that constitutes a flux recovering device (10A) is formed at the periphery of a rotating shaft (14), said periphery being on the side that faces the fan of a motor base (16). The drain section (20) surface facing the fan forms a tilted surface (20A) that tilts toward an outlet (46) provided on the rear side of the motor base (16) from the flat surface position of the motor base (16). The flux gathered to the center portion of the motor base (16) by rotary drive of the fan is made to flow into the drain section (20) formed at the center portion of the motor base (16) and to flow along the tilted surface (20A), and the flux is stored in a recovering container (34) from the drain section (20) via the outlet (46), a drain tube, and a pipe (48).