PURPOSE: To rapidly and effectively deodorize a malodor and to hold deodorizing effect for a long period of time by using magnesium oxide as the main component of a deodorizing material of a malodor generated from org. matter.

CONSTITUTION: Magnesium oxide is used as the main component of a deodorizing material of a malodor generated from a substance mainly containing putrefactive and fermentable org. matter. A mixture of magnesium oxide with natural zeolite and/or a porous carbonaceous substance such as powder coal is used. When the deodorizing material is scattered on the surface of a malodor generating substance to be mixed with said substance, magnesium oxide is reacted with a malodor to achieve deodorizing effect and synergistic deodorizing is performed by the physical adsorbing action of the porous substance. By this method, a malodor is deodorized rapidly, effectively and inexpensively and deodorizing effect is held for a long period of time.