Provided is a cooler that can extend a cooling function by at least making a latent heat storage material dormant during a physical distribution process. A cooling tool used for logistics packaging containers that regulates the temperature of objects to be cooled, has supercooling characteristics, and has a solidification temperature at which the phase changes from a liquid phase to a solid phase and a phase change from a solid phase to a liquid phase. A latent heat storage material having a temperature range as a dormant period between the melting start temperature to be started, and a storage section for storing the latent heat storage material, wherein the latent heat storage material is a temperature at which an object to be kept cool is to be held. Depending on the range, the main melting temperature is included in the temperature range in which the object to be kept cool is to be maintained, and at least the temperature range in the sleep period and the temperature range in which the object to be kept cool is to be kept have an overlapping range. Was selected as follows.物流の過程で潜熱蓄熱材を少なくとも休眠させることで、冷却機能を延長させることができる保冷具を提供する。物流梱包容器に用いられ、保冷対象物の温度調節を行なう保冷具であって、過冷却特性を有し、液相から固相に相変化し始める凝固温度と固相から液相に相変化し始める融解開始温度との間の休眠期としての温度範囲を有する潜熱蓄熱材と、前記潜熱蓄熱材を収容する収容部と、を備え、前記潜熱蓄熱材は、保冷対象物の保持されるべき温度範囲に応じて、主たる融解温度が前記保冷対象物の保持されるべき温度範囲に含まれ、少なくとも前記休眠期の温度範囲と前記保冷対象物の保持されるべき温度範囲とが重複する範囲を有するよう選択されたものである。
