This review article is intended to introduce periglacial environment present and past in Japan, and to summarize some studies on it. The periglacial climate in Japan is characterized by a wide annual range of air temperature and much snow accumulation in winter. This makes for local variability in appearance of periglacial processes on the mountain slopes near crests. In Japan, the main interest in periglacial studies concerns the abovementioned variability and its causes, that is, how periglacial processes relate to vegetation, local climate especially snow accumulation and its seasonal duration, soil, micro-relief, properties of bed rock etc.Seasonal soil freezing was measured in lowlands of Hokkaido. Depth of frost penetration without snow cover increases proportionally to the increments of accumulated degreedays. Depth of frost penetration on natural conditions is affected not only by the degreedays but also by the depth of snow cover which differs locally even within a small area.The oldest frozen ground phenomena was recognized in a horizon about 50,000 years old in the lowlands of Hokkaido. Involutions about 40,000 years ago exceeded active earth hummocks in size. And the phenomena reached the maximum phase as represented by icewedge casts of Spfa pumice (ca. 32,000 abp). Another climatic deterioration started a little before 20,000 years ago, which is shown by large size involution and pseudo-morphs of icewedge casts of the En-a pumice (ca. 15,000 abp). Most of fossil features are covered with undisturbed Ta-d pumice (ca. 9,000 abp), but earth hummocks and vertical stones have been still formed in the Holocene tephra layers.
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