Inotodiol, a lanostane-type triterpenoid, and many phytochemicals from Chaga mushroom have been investigated for various allergic diseases. However, antiaging and anti-inflammatory activities of inotodiol under different types of oxidative stress and impact of inotodiol on collagen and hyaluronan synthesis are not sufficiently studied. Lanostane triterpenoids-rich concentrate, which contained 10% inotodiol as major (the inotodiol concentrate), was prepared from Chaga and compared with pure inotodiol in terms of anti-inflammatory activities on a human keratinocyte cell line, HaCaT cells, under various stimulation such as stimulation with ultraviolet (UV) B or tumor necrosis factor (TNF)-α. In stimulation with TNF-α, interleukin (IL)-1β, IL-6, and IL-8 genes were significantly repressed by 0.44~4.0 μg/mL of pure inotodiol. UVB irradiation induced overexpressions of pro-inflammatory cytokines, but those genes were significantly suppressed by pure inotodiol or inotodiol concentrate. Moreover, pure inotodiol/inotodiol concentrate could also modulate synthesis of collagen and hyaluronic acid by controlling COL1A2 and HAS2/3 expression, which implies a crucial role of pure inotodiol/inotodiol concentrate in prevention of skin aging. These results enlighten anti-inflammatory and anti-aging effect of pure inotodiol/inotodiol concentrate, and it is highly conceivable that pure inotodiol and inotodiol concentrate could be promising natural bioactive substances to be incorporated in therapeutic and beautifying applications.