To provide a carrier base material for an exhaust gas cleaning catalyst being hardly damaged as compared with a conventional one even if it is used near an engine.

The carrier base material for the exhaust gas cleaning catalyst is a carrier base material for an exhaust gas cleaning catalyst of a quadrangle cross section having a plurality of cells 2 divided by a partition wall 1 made of ceramics and penetrating in a predetermined direction. At least one side of the cell 2 is adjacent to at least two cells 2 through one side. Further, the exhaust gas cleaning catalyst comprises the carrier base material for the exhaust gas cleaning catalyst; and a catalyst component carried on an inner surface part of the cell 2.