PROBLEM TO BE SOLVED: To provide a cold insulation tool capable of easily acknowledging in view whether or not a cold state is kept at a state to be object.SOLUTION: This invention relates to a cold insulation tool having cold insulation composition including water, a deposition component, a non-deposition component and pH indicator. The deposition component is deposited when the cold insulation composition is frozen and does not correspond to the pH indicator, and the non-deposition component is not deposited when the cold insulation composition is frozen and does not correspond to the pH indicator. The cold insulation composition is set such that pH(&alpha) when the deposition component and inclusion component other than water are replaced with water is 4.5 or more and lower than 7.0, pH(&bgr) when the non-deposition component and the inclusion component other than water are replaced with water is 5.5 or more and less than 10.3, and pH(&alpha) and pH(&bgr) indicate values in pH ranges different to each other in three pH ranges with pH lower than discolor range of the pH indicator, pH in the discolor range and pH higher than the discolor range.
