A device is disclosed for separating a mixture of free gas and liquid at the intake of a pump connected to a bottom end of a tubular column at the bottom of a drilled well. The pump is connected to the tubular column by an intermediate production tube and is introduced into a fluid intake device a bottom end of which is closed and a top end comprises fluid introduction orifices, said pump being placed inside said intake device, close to its bottom end, said intake device comprising, close to its bottom end, a device forming at least a check valve.