Stress occurring in a moving blade in a gas turbine stopping process is decreased. Time t1 is load decrease start or fuel throttling start, time t2 is no load operation start, time t3 is fuel shut-off and time t4 is a time of largest stress. A 4/4 load maintained until t1 decreases gradually to a 0/4 load at t2, which is then maintained until t3 and then decreases further. The rotational speed is the rated speed until t2, at which point it is controlled to be decreased gradually to about 60% of the rated rotational speed at t3. The metal differential temperature between a moving blade point A and a platform point B is constant until t1 and is then decreased slightly between t1 and t2 and between t2 and t3. Differential temperature &Dgr;t, largest after t3, occurs at t4. Stress occurring in the moving blade, while decreasing between t1 and t3, becomes largest at t4 by the effect of centrifugal force and thermal stress, but as the rotational speed is decreased to about 60% of the rated rotational speed at t3 and the metal temperature is also decreased as compared with the prior art, the influence of the centrifugal force and the differential temperature is decreased, whereby stress occurring in the moving blade is mitigated.