Abstract: Provided is a liquid retainer having a simple structure capable of cooling and warming a part of a human body, predetermined devices, and the like. A liquid retainer includes: a pouch having water blocking properties and flexibility and formed into a pouch shape; and a three-dimensional knit including: a plurality of mesh-like knit garments arranged substantially parallel to each other; and a plurality of coupling strands for coupling the plurality of mesh-like knit garments to each other. The plurality of coupling strands of the three-dimensional knit are made of elastic chemical fiber. The three-dimensional knit is formed into a substantially flat-plate-like shape and arranged in the pouch. Further, the three-dimensional knit retains liquid in the pouch.