An object of the present invention is to provide a sealing material for a honeycomb structured body, which can secure safety for human body of the sealing material for a honeycomb structured body containing inorganic fibers, does not form a gel and has good applicability to ceramic blocks and the like even long after preparation of the sealing material for a honeycomb structured body. The sealingmaterial for a honeycomb structured body according to the present invention contains inorganic fibers including a biosoluble inorganic compound; inorganic particles; and an ion adsorbent in an amountof 0.1% by weight or more.