Abstract: A reflow soldering method and the apparatus thereof is described for soldering a base board having electronic elements located thereon by an inert gas circulated through heater means in a plurality of chambers while the base board is transported through all the chambers, the inert gas being circulated by ventilating means driven by drive means, the method and the apparatus thereof comprising a shield case for enclosing at least the chambers, the ventilating means and the drive means to shut off the same from an outer air and refrigerating means for cooling down the inert gas in the shield case.

Abstract: A reflow soldering method and the apparatus thereof is disclosed, wherein an air flowing fan is provided at the bottom of the apparatus, that is, below a work transporting conveyor so as to produce a minus pressure to draw or pull air into the apparatus in a manner that the drawn air may flow in a constant volume and at a constant speed from up to down through a predetermined path and flow down through a heater provided in the path to be heated up substantially to a set temperature of the heater. The heated air further flows down to contact a work such as a base board having electronic parts mounted thereon and transported by the conveyor and heat up the work.