NOVELTY - The method involves coating (S1,S2) solution consisting of carrier and metal oxide precursor of catalyst metal to corrugated substrate (1) of metal foil and flat-shaped substrate (2) of flat shaped metal foil. The coated solution is dried (S3,S4) for forming catalyst layer. The corrugated substrate is laminated with flat-shaped substrate using catalyst layer. The laminated corrugated substrate and flat-shaped substrate are welded with each other to form spiral honeycomb structure (28).    USE - Method for manufacturing metal honeycomb catalyst apparatus (claimed) used for exhaust gas processing apparatus of fuel cell of motor vehicle and two-wheeled vehicle.    ADVANTAGE - The metal honeycomb catalyst apparatus is manufactured effectively with high stability, by welding corrugated substrate with flat-shaped substrate to form honeycomb structure.    DETAILED DESCRIPTION - The contacting portion is made to contact the vertex of corrugated substrate and flat-shaped substrate. The honeycomb structure in heated to temperature of 200-700 degrees C, after welding process. The coating process is performed by electrostatic spray coating process. The laser welding is carried out at vertex of laminated corrugated substrate and flat-shaped substrate. An INDEPENDENT CLAIM is included for a metal honeycomb catalyst apparatus has catalyst layer whose density in contact portion of corrugated substrate and flat-shaped substrate is higher than density of catalyst layer in not contacting portion of corrugated substrate and flat-shaped substrate. The surface roughness of the catalyst layer of portion is provided larger than the particle diameter of the carrier of catalyst metal in the catalyst layer. Only the edge portions of corrugated substrate and flat-shaped substrate are welded in width direction parallel to the direction orthogonal to the winding-up direction of corrugated substrate and flat-shaped substrate.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view illustrating the process of manufacturing metal honeycomb catalyst apparatus. (Drawing includes non-English language text)    Corrugated substrate (1)    Flat-shaped substrate (2)    Spiral honeycomb structure (28)    Steps for coating solution to corrugated substrate and flat-shaped substrate (S1,S2)    Steps for drying coated solution (S3,S4)