Abstract: A holding seal material includes inorganic fibers, skin layers provided around the inorganic fibers, inorganic particles included in the skin layers, a first main surface, and a second main surface. Thicknesses of the skin layers satisfy X>Y?Z. X is a thickness of the skin layer of the inorganic fibers in a vicinity of the first main surface. Y is a thickness of the skin layer of the inorganic fibers in a vicinity of a center of the holding seal material in a thickness direction. Z is a thickness of the skin layer of the inorganic fibers in a vicinity of the second main surface.

Abstract: A retaining seal material includes inorganic fibers, inorganic particles adhering to surfaces of the inorganic fibers, a first principal surface, and a second principal surface. A mean particle diameter of the inorganic particles in a vicinity of a center in a thickness direction of the retaining seal material is smaller than at least one of a mean particle diameter of the inorganic particles in a vicinity of the first principal surface and a mean particle diameter of the inorganic particles in a vicinity of the second principal surface.

Abstract: A holding sealing material includes a mat, an inorganic binder and an organic binder. The mat includes inorganic fibers and has an upper part, a center part, and a lower part in a thickness direction. The inorganic binder is loaded on the mat. The organic binder is loaded mainly on the upper part and the lower part of the mat. The holding sealing material is disposed between an exhaust gas-treating body and a casing for housing the exhaust gas-treating body to form an exhaust gas purifying apparatus.

Abstract: A retaining seal material includes inorganic fibers, inorganic particles adhering to surfaces of the inorganic fibers, a first principal surface, and a second principal surface. A mean particle diameter of the inorganic particles in a vicinity of a center in a thickness direction of the retaining seal material is smaller than at least one of a mean particle diameter of the inorganic particles in a vicinity of the first principal surface and a mean particle diameter of the inorganic particles in a vicinity of the second principal surface.

Abstract: A holding seal material includes inorganic fibers, skin layers provided around the inorganic fibers, inorganic particles included in the skin layers, a first main surface, and a second main surface. Thicknesses of the skin layers satisfy X>Y?Z. X is a thickness of the skin layer of the inorganic fibers in a vicinity of the first main surface. Y is a thickness of the skin layer of the inorganic fibers in a vicinity of a center of the holding seal material in a thickness direction. Z is a thickness of the skin layer of the inorganic fibers in a vicinity of the second main surface.