Hepatic stellate cell (also referred to as Ito cell, fat-storing cell, perisinusoidal cell, lipocyte) is one of the sinusoid-constituent cells that play multiple roles in liver pathophysiology. Although identification of the stellate cell had taken about 100 years because of the misconception caused by the discoverer von Kupffer, Wake made a great contribution to the "re" discovery of the cell in 1971. Establishment of the isolation of hepatic non-parenchymal cells from rats by Knook has made it possible to uncover the metabolic function of individual cells. Now, the stellate cell function is expanding from a retinol (fat)-storing site to a center of extracellular matrix metabolism and mediator production in the liver. Function as a liver specific pericyte has also been elucidated. Transition of the stellate cells from the vitamin A-storing phenotype to "activated" or "myofibroblastic" cells that produce a large amount of type I collagen and transforming growth factor beta triggers the progress of liver fibrosis in the course of hepatic inflammation. Communication of the stellate cells with the other hepatic constituent cells and invading inflammatory cells is also an important factor that regulates the local pathological reaction. Analysis of cellular and molecular aspects of the stellate cell activation would lead to the establishment of a novel therapeutic strategy against the progress of liver fibrosis in human liver disease.