Device for the in vitro culture of cells comprising: a planar deformable substrate ( 3 ) with a culture surface ( 4 ), substrate deforming means for modifying the size of said culture surface ( 4 ), characterized by the fact that it furthermore comprises: substrate holding elements ( 5 ) which are located near the periphery of said culture surface ( 4 ), a frame ( 6,8 ) surrounding and directly or indirectly fixing said substrate holding elements ( 5 ), in such a way as to allow microscope viewing of the culture surface ( 4 ) and to avoid mechanical parts directly above or below the culture surface ( 4 ), said frame ( 6,8 ) being adapted to move said substrate holding elements ( 5 ) away from the center of said culture surface ( 4 ).