PURPOSE: To manufacture a superbly reliable manifold by affixing a bonding agent on a bonding surface of a cover block, coating said layer with a sheet of breathing structure all over, and providing additionally a bonded surface of a main block on the sheet and bonding thereon.

CONSTITUTION: A bonding agent 3 is applied on a bonding surface 2 of a cover block 1, and said bonding agent 3 layer is coated with a breathing sheet 4. Then, the bonding agent 3 passes through fine space of the breathing sheet 4 and oozes out on the upper surface of the sheet 4 to form a thin- and uniform bonding agent layer 3a on the surface layer of the sheet, and a main block 5 and the cover block 1 are bonded integrally after affixing a bonding surface 6 of the main block 5 on said sheet 4. At that time, foams are prevented from remaining on the bonding surface 6 of the main block by means of the bonding agent layer 3a formed on the sheet surface layer. Also, fluidity in the horizontal direction of the bonding agent 3 is disturbed by the breathing sheet 4, and the bonding agent 3 between bonding surfaces 6 and 2 is cured without protruding into a channel 7. Also, the breathing sheet 4 works as a spacer to make the thickness of the bonding agent layer 3a of the surface layer uniform.