Abstract: A nasolacrimal stent device illuminates a dark nasal cavity so that the interior of the nasal cavity can be directly observed to facilitate and ensure the correct insertion of a nasolacrimal stent into the nasal duct. Flexible, transparent probe tube segments (21) are connected to the opposite ends of a flexible detention tube segment (2) having a diameter that permits the flexible detention tube segment (2) to be inserted in a lacrimal passage, respectively. The respective extremities of distal end parts (21a, 21b) of the probe tube segments (21) are closed. The probe tube segments (21) are provided in their base end parts with openings (23), respectively. When inserting each probe tube segment (21) into the nasal cavity, an illuminating device, such as an optical fiber (30) is inserted through the opening (23) into the probe tube segment (21) to illuminate the interior of the nasal cavity through the transparent probe tube segment (21).