The gaseous flow contg. combustible components is passed through two stationary layers of neutral heat-accumulating material and an intermediate layer of catalyst between them. The direction of flow is periodically changed to opposite. The gaseous flow contg. combustible components in an amount of 0.3-1 g/m3 is passed through the catalyst layer with linear velocity 1.2-10 times higher than the velocity of passage through neutral layers. The gaseous flow contg. combustible components in concn. 2-10 g/m3is passed through the catalyst layer with linear velocity 1.2-10 times lower than the velocity of passage through neutral layers. The magnitudes of linear velocities are related to total cross-sections of layers within indicated intervals of concn..    In examples, the combustible component is e.g. butanol, methanol, formaldehyde, acetone, toluene, xylene, butane, propane, butylacetate, ethylcellulose, benzene, ethylhexane, methanol, etc.. The temp. of reaction mixture is 20-130C, the height of catalyst layer is 0.25-1.8 m; the height of neutral layer is 0.4-2.1 m; the time of cycle is 12-48 min.; the total hydraulic resistance of layers is 100-8200 Pa.    The unit comprises catalytic reactor (1), four-position valve-switch (2), and pipe connections. The catalytic reactor contains three layers (3-5) with the middle catalyst layer (3) of lower cross-section in this case of gaseous flow with low content of combustible components. The end layers (4,5) are of neutral material. This configuration ensures a higher linear velocity of flow in catalyst layer than in the neutral layers. The reactor is first heated to the required temp., e.g. 350C, and gaseous flow input at a lower temp. e.g. 20-150C.    USE -   In methods of catalytic neutralisation of industrial gaseous waste for elimination of harmful admixtures, which are useful in chemical, petrochemical, metallurgical, and other branches of industry.    ADVANTAGE -   The method of neutralisation has high efficiency in a wider range of concn. of admixtures and reduced cost. It can be utilised in the case of gaseous wastes with low and high contents of organic cpds., with reduced hydraulic resistance of reactor, lower energy consumption and longer lifetime of catalyst.