To better understand changes in snow density in summer and formation of snow stratification, we investigated temporal changes of surface snow density and its spatial distribution. Two types of snow-density measurements were performed. (i) With a rectangular sampler, snow density was measured with 3-cm resolution in depth to a depth of 21 cm. (ii) With a cylindrical sampler, snow density at the ... surface 11.5 cm was measured. Each of two types measurements was done every other 10km by turns. Weight of the snow was measured using both electronic balance and mechanical balance. These measurements were done at plateau sites where elevation was more than ~3000 m. Measurements were done along a route connecting “Relay Point (74°0’S, 43°00’E, and 3353-m a.s.l.) – Dome Fuji (77°19’ S, 39°42’ E, and 3810-m a.s.l.) – JASE Meeting Point (75°53’S; 25°50’E; 3661 m a.s.l.) – Dome Fuji – Relay Point”. In particular, along a route between Relay Point and Dome Fuji, the first set of data was acquired in a period from December 2nd to 9th, 2007. The second set of data was taken during a period from January 10th to 15th 2008. By the comparison, we found significant temporal changes.