Disclosed is an analgesic agent for a non-inflammatory pain disease, which comprises a sialic acid or a pharmaceutically acceptable salt thereof as an active ingredient. The sialic acid which is an active ingredient for the agent has an analgesic effect on a disease model animal of neurogenic pain which is an non-inflammatory pain. Therefore, the analgesic agent is useful as a pharmaceutical agent for the treatment of an non-inflammatory pain disease such as an neurogenic pain disease, e.g., trigeminal neuralgia, postherpetic neuralgia, entrapment neuropathy, complex regional pain syndrome, diabetic neuropathy, traumatic neuropathy, phantom limb pain, central pain after spinal cord injury or stroke, and neuropathy caused by pharmacotherapy or radiation therapy, or the like.