Numerous studies have shown that pain sensation is affected by various immune-related molecules such as cytokines in tissues constituting sensory pathway. Interleukin (IL)-27 has been reported to have an anti-inflammatory effect through regulation of T cell differentiation, especially Th17 cells, and induction of IL-10-producing Tr1 cells. Although IL-17 and IL-10 are reportedly involved in pain sensation, roles of IL-27 in pain sensation have yet to be determined. Here we show evidences that constitutive existence of IL-27 controls threshold of pain sensation in various pathophysiological conditions. Mice lacking IL-27 signaling possessed chronic pain-like hypersensitivity. Reconstitution with IL-27 in these mice quickly restored the hypersensitive threshold of aversive behavior, suggesting the mechanisms were independent of cytokine induction, such as IL-10. In addition, the mechanism by which IL-27 controlled pain-like behavior did not involve well-known pain-related molecules, such as prostaglandins and opioids. Our data shed new lights on the role of IL-27 in pain control and pain-related disorders, aside from its immunoregulatory roles.