<p>A metal hydride reactor comprising a tubular pressure receptacle (7) having an opening at its one end and containing a metal hydride (3) filled therein, at least a part of the outer wall surface of the tubular pressure receptacle (1) forming a heat-exchanging surface; a heat-conducting fin (2) of a heat-conducting material provided to transmit heat from the metal hydride (3) in the pressure receptacle (1) to the heat-exchanging surface and limit the location of the metal hydride (3) in the pressure receptacle (1); and at least one porous member (4) extending axially of the receptacle (1) for forming within the receptacle (1) a hydrogen gas flow passage leading to said opening of the receptacle (1), said porous member (4) being permeable to hydrogen gas but impermeable to the metal hydride.</p>
