Support tower (3, 30), particularly for a wind turbine, wherein said support tower (3, 30) comprises: at least a first elongated component (10, 31), which is internally hollow; at least a second elongated component (11, 32), which is slidably coupled to said at least a first elongated component (10, 31) and movable relative to said at least a first elongated component (10, 31) at least between a retracted position, where said second elongated component (11, 32) is at least partially inserted in said at least a first elongated component (10, 31), and an extracted position, where said at least a second elongated component (11, 32) is substantially extracted from said at least a first elongated component (10, 31); moving means (22a, 22b, 22c, 22d; 36, 39, 40) for moving said second elongated component (11, 32) from said retracted position to said extracted position, and vice versa; blocking means (15, 41) configured to allow said at least a second elongated component (11, 32) to be blocked in said extracted position; and the support tower (3, 30) being characterized in an anti-falling system which comprises: at least one longitudinal element longitudinally fixed to an inner part of said at least a first elongated component, a plurality of longitudinal holes being formed in said at least one longitudinal element; at least one sliding member, which is fixed to an outer part of said at least a second elongated component and slidably coupled to the at least one longitudinal element; a plurality of pins, each movable between a respective position of engagement with a hole of said plurality of longitudinal holes, and a respective position of disengagement with a hole of said plurality of longitudinal holes; at least one inserting member fixed to said at least one sliding member such that, when said at least one sliding member moves from said retracted position to said extracted position, said at least one inserting member moves, in a sequential way from bottom upwards, pins of said plurality of pins from respective disengagement position to respective engagement position, this preventing said second elongated component from falling when said support tower is vertically arranged. at least a first elongated component (10, 31), which is internally hollow; at least a second elongated component (11, 32), which is slidably coupled to said at least a first elongated component (10, 31) and movable relative to said at least a first elongated component (10, 31) at least between a retracted position, where said second elongated component (11, 32) is at least partially inserted in said at least a first elongated component (10, 31), and an extracted position, where said at least a second elongated component (11, 32) is substantially extracted from said at least a first elongated component (10, 31); moving means (22a, 22b, 22c, 22d; 36, 39, 40) for moving said second elongated component (11, 32) from said retracted position to said extracted position, and vice versa; blocking means (15, 41) configured to allow said at least a second elongated component (11, 32) to be blocked in said extracted position; and the support tower (3, 30) being characterized in an anti-falling system which comprises: at least one longitudinal element longitudinally fixed to an inner part of said at least a first elongated component, a plurality of longitudinal holes being formed in said at least one longitudinal element; at least one sliding member, which is fixed to an outer part of said at least a second elongated component and slidably coupled to the at least one longitudinal element; a plurality of pins, each movable between a respective position of engagement with a hole of said plurality of longitudinal holes, and a respective position of disengagement with a hole of said plurality of longitudinal holes; at least one inserting member fixed to said at least one sliding member such that, when said at least one sliding member moves from said retracted position to said extracted position, said at least one inserting member moves, in a sequential way from bottom upwards, pins of said plurality of pins from respective disengagement position to respective engagement position, this preventing said second elongated component from falling when said support tower is vertically arranged. at least one longitudinal element longitudinally fixed to an inner part of said at least a first elongated component, a plurality of longitudinal holes being formed in said at least one longitudinal element; at least one sliding member, which is fixed to an outer part of said at least a second elongated component and slidably coupled to the at least one longitudinal element; a plurality of pins, each movable between a respective position of engagement with a hole of said plurality of longitudinal holes, and a respective position of disengagement with a hole of said plurality of longitudinal holes; at least one inserting member fixed to said at least one sliding member such that, when said at least one sliding member moves from said retracted position to said extracted position, said at least one inserting member moves, in a sequential way from bottom upwards, pins of said plurality of pins from respective disengagement position to respective engagement position, this preventing said second elongated component from falling when said support tower is vertically arranged.