To provide an inexpensive and light weight-thermal insulating panel having a small installing area in which it has a superior thermal insulating performance capable of completely shutting off both giving and receiving of heat between the two regions of a high temperature side and a low temperature side partitioned by the thermal insulating panel and further having a heat exchanging function.

The thermal insulating panel (1) is provided with an evaporating space (3) having evaporating liquid (4) filled therein within a panel main body (2) composed of a flat plate. The evaporating liquid (4) can be evaporated at a lower temperature than a temperature in a high temperature region and a cooling water flow passage (6) is formed on an upper wall surface (3a) of the evaporating space (3). At the evaporating space (3) in the thermal insulating panel (1), heat from the high temperature side region is used as evaporating latent heat for the evaporating liquid (4), the vapor ascends and is contacted with the upper wall surface (3a) to release latent heat of condensation to the upper wall surface (3a) and the vapor returns to its liquid state. Accordingly, a substantially constant temperature is kept at the evaporating space (3) and it is possible to restrict the emission of heat to the low temperature side region.