The present invention relates to a holding material for a catalyst converter, where the catalyst converter contains a catalyst carrier having a cross-section of a flattened shape, a metal casing to which the catalyst carrier is received, and the holding material attached to the catalyst carrier and interposed in a gap between the catalyst carrier and the metal casing, in which the holding material has a first part positioned in a minor axis direction of a cross-section of the catalyst carrier and having a high basis weight, a second part positioned in a major axis direction of the cross-section of the catalyst carrier and having a low basis weight, and a third part having a basis weight gradually decreased toward the second part from the first part.