A catalytic converter holding mat that is inexpensive, and exhibits an excellent heat insulation capability is provided by utilizing an inexpensive heat insulating material that exhibits an excellent heat insulation capability. The catalytic converter holding mat is provided in a gap between a tubular catalyst carrier and a casing that houses the catalyst carrier, and includes a retaining section that is formed of first inorganic fibers having a thermal shrinkage ratio at 1000° C. of 1% or less, and an insulation section that is disposed adjacent to the retaining section, and formed of second inorganic fibers having a thermal shrinkage ratio at 1000° C. of more than 1%.