An object of the present invention is to provide a combustion device which does not cause an increase in the amount of generated NOx or a degradation in efficiency due to a lower flame luminance, even when the combustion space is limited in the lengthwise direction of the flame. A fuel ejector is configured so as to be provided with at least a first fuel ejector and a second fuel ejector lined up in a specific direction as viewed in the lengthwise direction of fuel ejection, and is configured so that a first ejection stream ejected from the first fuel ejector and the second fuel ejector collide on the downstream side of ejection.