A freezing packaging film having transparency that produces a color difference (ΔE) of 30 or less on a surface of contents when subjected to frozen storage at −20° C. for 2 weeks, the contents being a reagent containing 0.14 mass % of methylene blue and having L* of 55 to 65, a* of 3 to 9 and b* of 45 to 55 in a L*a*b* color system.