The burning intensity of inverted flame base has been studied by using Infrared Rays Emission Computed Tomography. The results substantiate the general concept of the influence of flame stretch and preferential diffusion on the burning intensity. Specifically it was found that the burning intensity increases (decreases) towards the inverted flame base for mixtures whose effective Lewis number is smaller (greater) than unity: this behavior is qualitatively opposite to that observed for regular Bunsen flame tip because of the reversed flame curvature. It is further demonstrated that a heat loss to the stabilizing rod and a flow acceleration toward the flame base appear to have very small influences on the flame behavior, while flame curvature exerts strong influence on these phenomena.