Dupuytren's contracture is characterized by increased fibrosis of the palmar aponeurosis, with eventual replacement of the surrounding fatty tissue with palmar fascial fibromatosis. We hypothesized that adipocytokines produced by adipose tissue in contact with the palmar aponeurosis might promote fibrosis of the palmar aponeurosis. We compared the expression of the adipocytokines adiponectin and leptin in the adipose tissue surrounding the palmar aponeurosis of male patients with Dupuytren's contracture, and of male patients with carpal tunnel syndrome (CTS) as the control group. We also examined the effects of adiponectin on fibrosis-related genes and proteins expressed by fibroblasts in the palmar aponeurosis of patients with Dupuytren's contracture. Adiponectin expression in the adipose tissue surrounding the palmar aponeurosis was significantly lower in patients with Dupuytren's contracture than in those with CTS. The expression of fibrosis-related genes and proteins, such as types 1 and 3 collagen and α-smooth muscle actin, was suppressed in a concentration-dependent manner by adding AdipoRon, an adiponectin receptor agonist. The expression of fibrosis-related genes and proteins was also suppressed by AdipoRon in the in vitro model of Dupuytren's contracture created by adding TGF-β to normal fibroblasts collected from patients with CTS. Fibrosis of the palmar aponeurosis in Dupuytren's contracture in males may be associated with adiponectin expression in the adipose tissue surrounding the palmar aponeurosis. Although fibroblasts within the palmar aponeurosis are often the focus of attention when elucidating the pathogenesis of Dupuytren's contracture, adiponectin expression in adipose tissues warrants closer attention in future research.