The spontaneous ignition induction time and temperature distribution were observed by performing experiments for granulated activated carbon. As the results of the experiments at the same amplitude, the critical spontaneous ignition temperature was decreased with increase of the time period, while, the ignition induction time was increased with the increase of the time period. The critical spontaneous ignition temperature was decreased with the increase of the amplitude for the shorter period. The temperature distribution of the sample showed the highest around ignition-point at center of the vessel and after ignition the highest temperature was moved toward surface of the vessel.