Neuropathic pain is the most difficult type of pain to control, and patients lose their motivation with a decrease in their quality of life. Nociceptive signals to the CNS are primarily transmitted by sensory afferent fibers to the dorsal horn of spinal cord, with further rostral spread to the ventral-posterior nucleus of the thalamus, somatosensory cortex and the anterior cingulate cortex (ACC). In our previous study, we demonstrated that neuropathic pain increased the release of glutamic acid associated with astrocytic activation in the ACC and decreased the level of GABA released at the synaptic cleft in this region associated with an increase in GABA uptake through increased GABA transporters (GATs) on astrocytes. However, the role of the astrocytes in the ACC region for the control of pain sensation has been yet to be elucidated fully. In this study, we investigated whether activated-astrocytes in the ACC region could directly induce pain behaviors. We confirmed that sciatic nerve ligation caused thermal hyperalgesia and tacticle allodynia in mice. Mild noxious heat stimuli significantly changed the morphology of astrocytes, as detected by a stellate morphology in the ACC of nerve ligated-mice compared to that of sham-operated mice, with increasing the release of glutamate at the synaptic cleft in the ACC. Under their condition, we further investigated whether astrocyte activation in the ACC could directly induce the changes in pain sensation. Using an optogenetic tool with channel rhodopsin-2 (ChR2), we demonstrated that selective photostimulation of glial fibrillary acidic protein (GFAP)-positive astrocytes in vivo decreased pain threshold. These findings provide evidence that astrocytic activation in the ACC may, at least in part, aggravated pain under a neuropathic pain-like state.