A table is provided which has variable dimensions, especially a long length, and is mainly used in offices and conferences. The base of the table is supported by feet (6) and carries table leaves (1,1) which are brought together at the longitudinal sides thereof, and an insert (8,81) which can be inserted in-between the leaves, can have different configurations and can be used as a support for various structures. The base of the table includes at least two transversal supports (2) provided with a central sunken channel region (20) from which two extension arms (21) respectively extended in opposite directions, the feet (6) being mounted on the arms, and lateral struts (4) supporting the table leaves (1,1) being arranged on the outside.