To provide a drainage panel and a heat insulating drainage panel, which wholly have water permeability, enable sump water oozed out of a concrete wall to be discharged through the whole of the drainage panel, prevent the formation of a pool between the concrete wall and the drainage panel, prevent excessive surface pressure from being generated by the sump water and prevent an overflow even during intrusion by the excessive sump water, and a construction method for the simple wall of a concrete underground structure.

The drainage panel is mounted on a concrete plate surface, and grooves are juxtaposed at least on one side of a resin foam plate having many voids communicating with one another.