Abstract: A reflow furnace control system is contemplated to give an optimum time-temperature profile of an object intended to be heated. The object is carried on a conveyor to move along a conveyor path in the reflow furnace during which it is heated by heaters disposed along the conveyor path. A data table is provided to store sets of control data relating to the conveyor speed and the operating temperatures of the individual heaters. Each set of the control data is closely associated with various conditional parameters indicative of configuration and material characteristics of the object and the required temperature to which the object is heated. Control data assigning section is interfaced with the data table so that it responds to the entry of the conditional parameters for retrieving from the data table a relevant control data. Based upon the retrieved control data, the furnace is controlled by the system to give an optimum time-temperature profile of the object.