To provide an clathrate catalyst wherein a titanium oxide-metal component are separated under a molecular unit condition and a catalyst of a gas- permeable porous sintered body contg. it.

A lamellar compd. with swelling ion exchanging properties is used as a host and titanium oxide and its activated metal are used as a guest to prepare an clathrate catalyst composite-coordinated by intercalation and an ion exchange reaction and in addition, a porous sintered body is prepd. by molding the clathrate catalyst. In the porous sintered body, as titanium oxide is divided and obstructed by the three-layered lattice of the lamellar compd., a sintered texture wherein ultrafine particle characteristics with no particle growing are kept is formed to exhibit a high catalytic activity.