A holding sealing material includes a mat including an inorganic fibrous material. In a plan view, the mat has a basic quadrangular shape consisting of long sides extending in a longitudinal direction and short sides substantially perpendicular to the long sides. The mat has a recessed portion at one of the short sides and a projected portion at another of the short sides, whereby the projected and recessed portions should fit to each other when the mat is rolled around a periphery of a member to be wrapped. In a cross-sectional view, the projected portion is a quadrangle and the recessed portion is a gap between two quadrangles. At least one corner portion of the projected portion is cut out on a side of the member to be wrapped or another corner portion of the quadrangle of the projected or recessed portions is cut out.