Device and method for separating a solution

In the present invention, a target substance-containing solution in an atomizer (1) is atomized into a mist, to produce a fluid mixture of mist and air. When collecting the mist from this fluid mixture is an air permeability membrane (51) having a pore size which air, but not the target substance contained in the mist passes, is used. In the present invention, the fluid mixture is contacted with the first surface of the air permeability membrane (51) in contact and produces a higher pressure than the pressure on the second surface of the opposite side on the first surface, thereby achieving that the air in the fluid mixture through the air permeability membrane (51) for separating a part or all of the air contained in the fluid mixture is passed.