Structure and procedure for erecting concrete towers used in wind turbines in which said towers consist of sections, which in turn may each comprise a different number of segments or longitudinal sections. The procedure includes two differentiated cycles, which may take place alongside each other: the pre-assembly of each section of tower and their assembly. The sections may be pre-mounted on bases placed on the ground, with the segment in turn fitted with the help of struts and mechanical clamps. This procedure is extremely versatile in that it makes the best logistic use of the material, resources and requisite assembly times since the assembly procedures for each section can be developed alongside each other in the different wind farm towers, and also greater heights can be achieved than is traditionally possible.