The effects of radiant heat fluxes on the stability range and burning velocity of a laminar premixed flame were examined by inserting a water-cooled Bunsen burner into a radiant heat recirculation-type furnace. The intensity of the radiant heat flux in the furnace was altered by regulating the surface temperatures of the furnace wall and downstream permeable plate. It was found that the flame blowoff and flashback limits were hardly affected by a radiation field as intense as the one surrounded by a refractory whose temperature was between 1250K and 1450K, and that no perceptible changes appeared either in the laminar burning velocity or flame thickness.