PROBLEM TO BE SOLVED: To provide a cold insulation tool that includes a composition for cold insulation having a short time for which it is maintained in a temperature range out of target, which is lower than a target cold insulation temperature, before reaching the target temperature during use after cooling.SOLUTION: A cold insulation tool includes a composition for cold insulation having water, a quaternary ammonium salt and an inorganic salt, the quaternary ammonium slat forms a clathrate hydrate, an eutectic point of the inorganic salt to water is -15°C or less, a concentration of the quaternary ammonium salt in the composition for cold insulation is less than a saturated concentration and 15.5 mass% or more and a content of the inorganic compound in the composition for cold insulation is 3 to 16 mass%.SELECTED DRAWING: None【課題】冷却後の使用時において、目的とする保冷温度に到達する前に、この保冷温度よりも低い目的外の温度範囲で維持される時間が短時間である保冷用組成物を備えた保冷具の提供。【解決手段】水、第４級アンモニウム塩及び無機塩を含有する保冷用組成物を備えた保冷具であって、前記第４級アンモニウム塩は、包接水和物を形成するものであり、前記無機塩の水に対する共晶点が－１５℃以下であり、前記保冷用組成物における前記第４級アンモニウム塩の濃度が飽和濃度未満で、且つ１５．５質量％以上であり、前記保冷用組成物の前記無機塩の含有量が３～１６質量％である、保冷具。【選択図】なし
