The effect of fuel particle shape on the reverse combustion process of a packed bed was investigated through the comparison of combustion of spherical-particle packed bed and non-spherical particle bed. In the experiment, we measured the combustion propagation rate at various superficial gas velocties by using the spherical and non-spherical granular activated carbon particles consisting of the same primary particles. Experimental results showed that the propagation rate of non-spherical particles was higher than that of spherical particles with the same diameter measured by sieves and that the rate of smaller particles was higher than that of larger particles. The combustion propagation rates were well correlated by the equivalent specific surface area obtatined by penetration method. This implies that the effect of particle shape on the reverse combustion of packed bed can be estimated by the penetration method.