Abstract: A catalytic converter comprises a generally elongated housing having gas inlet and outlet at its opposite ends, at least first and second catalyst carriers held in position inside the housing in axially spaced relation, a spacer assembly positioned inside the housing between the first and second catalyst carriers for holding them in the axially spaced relation, and an air supply piping having one end adapted to be fluid-connected to a source of fresh air and the other end communicated to the space between the catalyst carriers. The spacer assembly has an axial and a transverse passages defined therein and is constituted by a pair of spacer components prepared from a metal sheet by the use of any known press work.