Sheet member and manufacturing method of the same, and exhaust gas processing device

A manufacturing method of a sheet member including inorganic fibers, the manufacturing method comprising:

• a step of providing fiber material including inorganic fibers, in which the inorganic fibers include a lump-shaped cohered fiber which coheres as a lump;
• a step of opening fibers of the fiber material;
• a step of preparing a material slurry from the opened fibers;
• a step of forming a molded body having a desired shape using the slurry;
• and
• a step of obtaining the sheet member including the inorganic fibers by compression drying the obtained molded body,
• wherein the fiber material is collected from a sheet member manufactured in a needling process.