PURPOSE: To increase the strength of resistance to release by improving the fluidity of a catalyst paste at the time of manufacturing a plate-shaped catalyst.

CONSTITUTION: Ammonium molybdate and vanadyl sulfate are blended with titanium oxide (average diameter of 1.5μm and with given particle diameter distribution) of a catalyst composition component, to which alumina silica fiber of average diameter of 2.5μm and average length of 250mm are added twice, and the fiber diameter of the alumina silica fiber added first is made to fine pieces to be in the range of equal to ten times or less to the average particle diameter of a catalyst component and also the fiber length of 100 times or less of the average particle diameter. Then alumina silica fiber of the same quantity as first is added and kneaded to prepare a catalyst paste and a catalyst is manufactured through a coating process. The apparent particle diameter distribution of the catalyst component is widened by the arrangement to improve the fluidity of the paste and the catalyst of high strength of resistance to release is manufactured by being mixed with reinforcing fiber added thereafter.