To provide a portable simple cooling system offerable for a purpose when arriving at a destination by properly and continuously cooling the system up to arriving at the destination by cooling the system while carrying a reagent, a drink, and food, and easily carriable by folding up the system when not needed.

A bottomed cylindrical vessel-shaped cold reserving agent 2a of a cold reserving agent is set in a cylindrical heat insulating material 2b, and a cooling object is put and cooled in this vessel-shaped cold reserving agent 2a. The cooling object can be efficiently cooled since the vessel-shaped cold reserving agent of 2a does not directly contact with outside air. This cooling effect can be further enhanced by putting a flexible sheet-like cover 1b like the whole constitution indicated in a drawing 1 by putting an integral object of the vessel-shaped cold reserving agent 2a and the cylindrical heat insulating material 2b in a bag-shaped heat insulating material 3a of a drawing 3 like a drawing 2. This vessel-shaped cold reserving agent 2a and the cylindrical heat insulating material 2b are integrally used, and are formed as a removable structure, and can be cooled in a freezing chamber ancillary to a domestic refrigerator. A grip as 1a of the drawing 1 is attached for being convenient for carrying to enable walking by hanging from the shoulder or holding by hand.