To provide a light-weight, inexpensive, and highly reliable plate-like heat pipe capable of withstanding the use in cold regions and those regions where weather conditions such as temperature and humidity are severe, suitable for cooling heating parts mounted on electric/electronic devices, transporters (automobiles, electric cars, planes, ships, rockets, and others) stored in the cold regions, using water as a working fluid, and using a pure copper as a container material.

This plate-like heat pipe comprises a copper container having a hollow part formed of two sheets of copper foils and sealed, an armored body formed of a sheet metal material having a heat receiving surface and heat radiating surface covering the outer surface of the copper container, the working fluid stored in the copper container, and a wick.