An object of the present invention is to provide a therapeutic agent or prophylactic agent which has an analgesic effect on both nociceptive pain and neuropathic pain and is effective in treatment of fibromyalgia. The present invention provides a therapeutic agent or prophylactic agent for fibromyalgia, said agent comprising as an effective ingredient a cyclohexane derivative exemplified by the formula below, or a pharmaceutically acceptable salt thereof or a prodrug thereof.