The moor with bog pools of various sizes and shapes are distributed on the gentle slope in North Alps, Central Japan.　These bog pools have been considered to be deteriorated by the human impact (Kawano 1981) and warming impact (Honda 1964、Oritani 2008). In order to reveal structure and dynamics of vegetation on Midagahara moor along Alpine route, we investigated 1) relationships between microtopography and distribution of plant communities, 2) fluctuation of areas and shapes of the bog pools across the ages based on the present survey with total station and the past survey (Matsumoto & Takeda 1986) and aerial photographs (1953-2006). On the bottom of upper side of the bog pools, there were the trenches. The water depth of the bog pools was less than 1m, and was shallower toward the lower side. Scirpus hondoensis occurred only in water depth of less than 30cm. Mosses (Sphagnum spp.) grew at the edge of the pools, and build up dikes. The relatively dry places between the pools were covered by grass (Molinia japonica) and sedges (eg. Carex blepharicarpa, Eriophorum vaginatum). The hummocks were scattered about the moor, and Sasa (Sasa kurilensis) and some tree species, such as Abies mariesii , grew on them. The shapes and areas of the bog pools have little changed concerning small pools(n=21, area: 0.2~14.1㎡) at least since 1985, and concerning large pools(n=3, area:28.9~189.7㎡) at least since 1953.