Abstract: The reactivities of chars were investigated for gasification with steam and carbon dioxide by thermogravimetry in the temperature range of 1100 to 1400℃ and at atmospheric pressure, and the results were compared to those of the previous work at temperatures below 1000℃, where the gasification velocity was chemically controlled. The parent coals of the six char samples differed in rank from brown coal to anthracite and from non-caking coal to strongly caking coal. The rate equation, f=1- exp( -aθb), designated as the modified volume reaction model, was applied to evaluating gasification reactivities using an average rate constant k.