To reduce the operating cost ascribable to the supply of an oxygen-containing gas in the regeneration of a wet-process desufurization absorbent for a coke oven gas to zero.

This process comprises bringing hydrogen sulfide and hydrogen cyanide in a coke oven gas 2 into countercurrent contact with an alkaline absorbent containing a catalyst in an absorption tower 1 to effect absorption, bringing the absorbent leaving the tower 1 into contact with an oxygen-containing gas in a regeneration tower 10 to effect its oxidative regeneration to separate and remove the contaminants in the form of free sulfur, thiosulfates, thiocyanates, etc., and recirculating the regenerated absorbent into the tower 1. The absorbent leaving the absorption tower is introduced into the tower 10 through a liquid ejector and is regenerated by oxidation with air 9 sucked by the degree of suction vacuum of the ejector. As a result, a blower heretofore necessary to blowing the oxygen-containing gas into the tower 10 can be dispensed with, therefore power consumption can be reduced, and a distributor into the regeneration tower need not be installed. Therefore, the opening and cleaning of the regeneration tower upon the stoppage of the distributor is not necessary. Thus, the cost of power for change-over into a preliminary tower and of opening and cleaning the regeneration tower can be reduced to zero.