To provide a moisture-absorbing and -desorbing gypsum plaster board which can be produced at a production cost equivalent to that of a moisture- absorbing and -desorbing gypsum plaster board produced by a conventional technique and has higher moisture absorption/desorption properties as compared with the conventional similar gypsum plaster board, while retaining strength equivalent to that of the conventional similar gypsum plaster board.

This gypsum plaster board contains gypsum, a moisture- absorbing and -desorbing material and calcium silicate hydrate powder.