To provide a blanking plate improving operation efficiency of operation to remove unnecessary parts of an inorganic fiber mat and to provide a method for producing sealing members.

The blanking plate 11 is provided with a substrate 12 and a platy blanking blade 13 stood from the substrate 12 to blank and process the sealing members for waste gas treating bodies from an inorganic fiber mat. A first blanking blade 14 is provided in a continuous annular form. The first blanking blade 14 forms the inside of the outer peripheral end of the inorganic mat into a part for forming the sealing members, makes the outside of the part for forming the sealing members as the frame-like unnecessary parts and blanks the inorganic fiber mat. Second blanking blades 15 are installed in a region on the outside of the first blanking blade 14 so as to carry out blanking from the interior of the frame to the outside of the frame of the unnecessary parts. Recessed parts 15a for making the blade tips discontinuous are formed in the second blanking blades 15. A method for producing the sealing members comprises tearing the unnecessary parts of the inorganic fiber mat from the part blanked with the second blanking blades 15 and removing the unnecessary parts.