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, a casing that defines a cold storage space has a heat insulating structure, a partition wall that faces the casing is provided at least at a top portion of the cold storage space, and a gap between the casing and the partition wall is filled with an ice slurry that is a mixture of brine and flake ice acquired by freezing the brine. In addition, it is possible to provide a supply port for supplying the ice slurry into the gap and a discharge port for discharging the ice slurry from the gap.