Patent ID: 8632620

Claim:
A holding sealing material comprising: inorganic fibers; a mat shape; a first end face and a second end face, the first end face and the second end face being approximately parallel in a width direction of the holding sealing material; a contact section including a first portion of the holding sealing material, the first portion having a first distance between the first end face and the second end face, the first distance being longest in a length direction of the holding sealing material; a void-forming section including a second portion of the holding sealing material, the second portion having a second distance between the first end face and the second end face, the second distance being shorter than the first distance of the contact section in the length direction of the holding sealing material; and the holding sealing material having a structure to provide a void in a vicinity of the first end face of the void-forming section and the second end face of the void-forming section in a state where the holding sealing material is rolled up so that the first end face of the contact section is made in contact with the second end face of the contact section, wherein at least one of the first end face and the second end face has a step formed by at least one projected portion, wherein a length of the projected portion in the void-forming section of the holding sealing material is shorter than a length of the projected portion in the contact section of the holding sealing material in the length direction of the holding sealing material, and wherein the length of the projected portion in the void-forming section of the holding sealing material is from about 1% to about 90% of the length of the projected portion in the contact section of the holding sealing material.