A series of actual size mine fire experiments were conducted in level and inclined roadway. The main purposes of the experiments were; - obtain fundamental data about air temperature change downwind of the mlne fire, - measurement of gas concentration in the air from the fire and - examine the reverse movement of heated air containing toxic gases along the roof from the mine fire. These data are indispensable for taking effective counter measures against the mine fire and also needed to make reasonable mine fire simulation by a computer. Veptilation air speed, pressure drop over the fire zone were also measured at the same time. The air temperature decreased almost exponentially with distance from the fire. The coefficient of the air temperature decrease was determined by the experiments. The ventilation air speed at upwind of the fire decreased as the fire developed. The higher the temperature of the fire zone and the initial air speed, the larger in the decrease of the speed. The reversal of the hot air near the roof of the roadway was observed when the ventilation air speed was less than 1.5 mls in the level roadway and 1.7 m/s in the downward ventilated inclined shaft. On the basis of these data, a mine fire simulation program for a personal computer was made and examined. Several examples of mine fire simulation by the program will be described. It is quite useful to consider the countermeasures for mine fire. It is also useful to let the personals working underground to know how fast the toxic gas spread and to keep their attention on mine fire and evacuation from underground at high level.