The inventors perfected the present invention as a result of a study into IK1 channel activators and a confirmation that a benzothiophene compound exhibits efficacy against visceral pain, inflammatory pain, osteoarthritic pain, neuropathic pain, or fibromyalgia. This compound, represented by formula (I), has IK1 channel activating action, and may be used as a drug to prevent or treat visceral pain, inflammatory pain, osteoarthritic pain, neuropathic pain, fibromyalgia, or the like. The IK1 channel activator may be used as a drug to prevent or treat inflammatory pain, osteoarthritic pain, neuropathic pain, or fibromyalgia.
