Abstract: In combustion using air preheated by regenerative direct heat exchange between exhaust gas and the combustion air using a regenerator as a heat exchange medium, the present invention relates to a low-NOx burner that is effective for reduction in NOx in a mid-temperature range which has been conventionally difficult to be realized and improves stability of the flame. According to this low-NOx burner, at an outlet of an air throat 24 for flowing a full quantity of the combustion air is disposed a burner tile 22 having an enlarged diameter portion 23 thereof whose diameter is larger than that of the outlet, and a fuel nozzle 19 for injecting the fuel from the enlarged diameter portion 23 of the burner tile is also provided.