Provided is a cold storage unit that has a high cold storage capacity, does not generate carbon dioxide, and enables recycling of the cold source. Also provided are a moving body and an ice slurry supply system. In the cold storage unit 1, a casing 4 that defines a cold storage space 5 has a heat insulating structure, a partition wall 6 that faces the casing 4 is provided at least at a top portion of the cold storage space 5, and a gap 50 between the casing 4 and the partition wall 6 is filled with an ice slurry 3 that is a mixture of brine and flake ice acquired by freezing the brine. In addition, it is possible to provide a supply port 40 for supplying the ice slurry 3 into the gap 50 and a discharge port 41 for discharging the ice slurry 3 from the gap 50.