To provide a treatment device equipped with a catalyst-supporting honeycomb structure, the device being for use in, for example, an exhaust gas purification treatment, hydrogen production by ammonia decomposition or the like, and a method for producing the same. The catalyst-supporting honeycomb structure is produced by forming the inorganic binder-containing functional catalyst-supporting corrugated glass paper without removing an organic binder originally contained in the glass paper and by using the corrugated glass paper in combination with the inorganic binder-containing functional catalyst-supporting flat glass paper. In the treatment device equipped with a catalyst-supporting honeycomb structure, a corrugated glass paper having an inorganic binder-containing functional catalyst supported thereon and a flat glass paper having the same inorganic binder-containing functional catalyst supported thereon are alternately stacked to form the catalyst-supporting honeycomb structure, and this catalyst-supporting honeycomb structure is packed in a casing.