Device for cementing a casing in a well bore, characterized in that it comprises: - on the well head side, shutter means, disposed within the casing, that control the opening and closing of at least one cementing aperture, said at least one cementing aperture making the interior of the casing communicate with the annular space situated between the external face of the casing and the internal wall of the well, - on the well bottom side, a packer mounted along the external face of the casing, comprising: - an expandable liner, called a first external liner, the opposite extremities of which are fixedly attached to said external face of the casing, this casing, the first external liner and its extremities together demarcating an annular volume, the shutter means furthermore commanding the opening and the closing of at least one expansion aperture which makes the interior of the casing and said annular volume communicate, this first external liner being liable to expand and get applied, in a tightly sealed manner, on an intermediate part of its length, against the wall of the well, - a second expandable liner, called a second internal liner 124), that extends between said casing and said first external liner, its extremities being also fixedly attached to the external face of said casing, - at least one communication passage between the exterior of the first external liner and said annular volume, characterized in that said at least one communication passage is situated on the packer side orientated towards the well bottom. - on the well head side, shutter means, disposed within the casing, that control the opening and closing of at least one cementing aperture, said at least one cementing aperture making the interior of the casing communicate with the annular space situated between the external face of the casing and the internal wall of the well, - on the well bottom side, a packer mounted along the external face of the casing, comprising: - an expandable liner, called a first external liner, the opposite extremities of which are fixedly attached to said external face of the casing, this casing, the first external liner and its extremities together demarcating an annular volume, the shutter means furthermore commanding the opening and the closing of at least one expansion aperture which makes the interior of the casing and said annular volume communicate, this first external liner being liable to expand and get applied, in a tightly sealed manner, on an intermediate part of its length, against the wall of the well, - a second expandable liner, called a second internal liner 124), that extends between said casing and said first external liner, its extremities being also fixedly attached to the external face of said casing, - at least one communication passage between the exterior of the first external liner and said annular volume, characterized in that said at least one communication passage is situated on the packer side orientated towards the well bottom. - an expandable liner, called a first external liner, the opposite extremities of which are fixedly attached to said external face of the casing, this casing, the first external liner and its extremities together demarcating an annular volume, the shutter means furthermore commanding the opening and the closing of at least one expansion aperture which makes the interior of the casing and said annular volume communicate, this first external liner being liable to expand and get applied, in a tightly sealed manner, on an intermediate part of its length, against the wall of the well, - a second expandable liner, called a second internal liner 124), that extends between said casing and said first external liner, its extremities being also fixedly attached to the external face of said casing, - at least one communication passage between the exterior of the first external liner and said annular volume, characterized in that said at least one communication passage is situated on the packer side orientated towards the well bottom.