Surface flow velocities on the ablation area of the Lirung Glacier were calculated from the results of six surveys since 1989 to 1996. The annual flow speeds were about 6 m a-1 on the upper part of the ablation area near the icefall and the summer speeds were about one and half times faster than that. Around 2 km downstream from the upper part, the annual speeds decreased to about 2 m a-1 and the summer speeds were a little faster than that. Ice thickness was estimated, using the laminar flow theory, to be about 100 m or more than that in the upper part and about 50 m in the lower part of the ablation area. The rate of surface lowering was also preliminarily estimated, using the continuity equation, to be a little less than 20 cm a-1 on the average in the ablation area.