A ceria-zirconia composite oxide includes at least one of lanthanum, yttrium, and praseodymium. A rate of a total content of the at least one rare earth element to a total content of cerium and zirconium is 0.1 at% to 4.0 at%. A content of the rare earth element present in near-surface regions, which are at a distance of less than 50 nm from surfaces of primary particles of the ceria-zirconia composite oxide, accounts for 90 at% or more of the total content of the rare earth element. An average particle size of the primary particles of the ceria-zirconia composite oxide is 2.2 microns to 4.5 microns. After a predetermined durability test, the intensity ratio I(14/29) of a diffraction line at 2 Theta=14.5 degrees to a diffraction line at 2 Theta=29 degrees and the intensity ratio I(28/29) of a diffraction line at 2 Theta=28.5 degrees to the diffraction line at 2 Theta =29 degrees respectively satisfy the following conditions: I(14/29)larger than or equal to 0.02, and I(28/29)less than or equal to 0.08.