The invention relates to a method for producing carbon monoxide consisting, during an adsorption step, in using N adsorbers (4A, 4B), wherein N is equal to greater than two, each of which follows, at an offset; the same period T cycle during which adsorption and regeneration phases succeed each other, in exposing, at the beginning of the adsorption phase, each adsorber to an eluting phase during which only a part of a nominal flowrate of the mixture is transferred to the adsorber until said adsorber is substantially carbon monoxide saturated while at least the second adsorber is maintained in the adsorption phase and a purified gaseous mixture is partially liquefied for producing a liquefied gaseous mixture, in storing said mixture in a capacity (7) and in transferring the liquefied gaseous mixture from the capacity to at least one column (11) for the separation thereof into a carbon monoxide rich product and, during at least one part of the adsorber eluting phases, the liquid level in the container is decreased and during at lest one part of the cycle outside of the eluting periods, said level is increased.