To provide a gas separation device by adsorption in a type called as VSA or MPSA provided with a module enabling to cover a wide use range and operation condition.

This device contains the module M arranged with a rotary device R reversely rotatable, an adsorption device A and at least one tank C in series between a user line L and a feed source S of a gas mixture to be separated. The rotary device R is alternately driven in one direction at first pressurization and a generation phase and in the opposite direction at second pressure decrease and a desorption phase.