PURPOSE: To facilitate the exchange of a deodorant and to efficiently carry out adsorption while passing the exhaust uniformly through the deodorant by packing the granular deodorant in a net, housing the net freely attachably and detachably in a vessel, and providing a cylindrical gas resistor protruding in the flowing direction of the exhaust in the vessel.

CONSTITUTION: One face of a vessel 3 is opened, and cylindrical gas resistors 2B protruding in the flowing direction of the exhaust are provided on specified regions of the closed face opposed to the open face. Plural vessels 3 are superposed on an exhaust storage cavity 1 having an inlet 1A for the exhaust from a dry ammonia process diazo copying machine and with one face opened, and an upper lid 4 having an exhaust port 4A is furnished on the uppermost vessel 3. The granular deodorant contained in the net 7 is packed in the vessels 3. The exhaust from the copying machine passes uniformly through the granular deodorant, and the gaseous ammonia in the exhaust is effectively adsorbed by the deodorant. The deodorant is exchanged by taking out the net 7 contg. the deodorant as such, and then packing the net contg. a fresh deodorant in the vessel 3.