To provide a heat insulating panel with good workability, which can maintain internal temperature in a refrigerator, a cooling storage or a low-temperature storage to retain humidity, so that moisture is hardly drawn from a stored matter.

This panel comprises, as an integrated unit, a pipe unit 18 having a connector part 12 at one end and including a plurality of slender heat exchange pipes 16 connected between main pipes 14 for respectively supplying and returning a heat exchange fluid; a heat insulating material 11 laminated on the pipe unit 18 and provided with each main pipe at one end; and a surface plate 20 provided at least on the pipe unit 18 side. This plate further comprises each main pipe 38 for respectively supplying and returning the heat exchange fluid having a connector 40 connected to each main pipe 14, a connecting member 36 connecting a plurality of panel bodies 11 in line while containing each main pipe 38, and a pipe fitting 34 connecting each connector part 12 provided on each main pipe 14 of the plurality of panel bodies to the connector 40 of the connecting member 36.