An object of the present invention is to provide a substance which can be used as an active ingredient for improving neuropathic pain having a novel mechanism of action different from those of currently available agents and, therefore, provide an improving agent for neuropathic pain which rarely interacts with currently available agents and also does not have adverse reactions similar to those of currently available agents. An improving agent for neuropathic pain due to a hyperalgesic response of the present invention as a means for resolution is characterized by comprising, as an active ingredient, a lyase (an elimination enzyme) which has an activity of degrading a chondroitin sulfate chain of a chondroitin sulfate proteoglycan, and is typified by chondroitinase ABC which selectively removes chondroitin sulfate and dermatan sulfate of a proteoglycan.
