Fibrosis is defined as the excessive accumulation of extracellular matrix (ECM) proteins. These excessive ECM proteins are produced by myofibroblasts, which are differentiated mainly from resident fibroblasts in response to tissue injury. In addition to the ECM proteins, the amounts of heparan sulfate, one of the sugar chains, and the proteoglycans attached with heparan sulfate chains are reported to be increased in the fibrotic tissues. However, the contribution of heparan sulfate and heparan sulfate proteoglycans to the development of fibrosis remains unclear. In this study, we found that heparan sulfate 6-O-sulfotransferase-2 (Hs6st2), a type of heparan sulfate transferase, is remarkably induced during fibrosis in the heart, liver, and kidney of mice. We also demonstrated that Hs6st2 was specifically expressed in myofibroblasts of mice with cardiac and liver fibrosis. Hs6st2 knockdown in cardiac myofibroblasts reduced the mRNA expression of fibrosis-related factors, such as Collagen1a1. In summary, this study revealed that Hs6st2 is specifically expressed in myofibroblasts in fibrotic tissues, promotes fibrosis, and can be a good target for the treatment for fibrosis.