A climbing head for hoisting a self-climbing protection system for construction works in buildings, the climbing head being releasably fastenable to a mast comprising two vertical beams having respective longitudinal outwardly protruding longitudinal lateral flanges at their rear portions and a plurality of support elements (2, 2a) fixed between the vertical beams at different heights; and comprising two vertical side plates, distanced from each other and linked together at their lower end portions and at their upper end portions; hinging means for tiltably coupling the upper portions of the side plates to the upper end of a hoist cylinder the lower end of which is coupled to anchoring means (5, 6) fastened to a rim portion of a floor slab of a building, the hoist cylinder being capable of adopting an extended position and a retracted position; a rocker member that is pivotal between a hoist position where its front portion protrudes from the side plates and engages the mast when the hoist cylinder extends towards said extended position for hoisting the mast, and a passing position, in which it allows the passage of the mast when the hoist cylinder retracts to said retracted position; a lower claw comprising a lower left claw member (10a, 10b) and a lower right claw member (10c, 10d) each protruding laterally beyond one of the side plates; lower locking means to lock each of the lower claw members (10a, 10b, 10c, 10d) in a locked position where it embraces one of said lateral flanges and an open position in which the lower claw members (10a, 10b, 10c, 10d) release said lateral flanges; characterized in that the climbing head further comprises an upper claw comprising an upper left claw member (11a, 11b) and an upper right claw member (11 c, 11d) each protruding laterally beyond one of the side plates, and upper locking means to lock each of the upper claw members (11a, 11 b, 11c, 11 d) in a locked position where it embraces one of said lateral flanges and an open position in which the upper claw members (11 a, 11 b, 11c, 11 d) release said lateral flanges (1 c); each of the claws members (10a, 10b, 10c, 10d, 11 a, 11 b, 11c, 11 d) comprises a fixed claw portion (10a, 10c, 11a, 11c) emerging from one side plate and a movable claw portion (10b, 10d, 11 b, 11 d) that is pivotal about a vertical rotation axis (12a, 12b), provided in the fixed claw portion (10a, 10c, 11a, 11c) to which it is mounted, between said locked and said open position; the locking means comprise lower and upper left locking means and lower and upper right locking means, the locking means comprising each a vertical bolt (13a, 13b; 15a, 15b) which, in the claw member's (10a, 10b, 10c, 10d, 11a, 11b, 11c, 11d) locked position, remains removably inserted in vertically aligned first throughholes (17a, 17b; 18a, 18b; 19a, 19b; 20a, 20b) respectively provided in the fixed (10a, 10c, 11 a, 11c) and in the movable claw portion (10b, 10d, 11 b, 11 d) between the respective vertical rotation axis (12a, 12b) and the respective side plate; the vertical bolts (13a, 13b) of the left locking means are connected to a left vertical rod that extends slidingly through second throughholes (21a, 21b) provided respectively in the left movable claw portions (10b, 11 b) at a position between its rotation axis and its free end; the vertical bolts (15a, 15b) of the right locking means are connected to a right vertical rod that extends slidingly through second throughholes (21 c, 21 d) provided respectively in the right movable claw portions (10d, 11d) at a position between its rotation axis and its free end; each of the vertical rods (14, 16) has a length such that their lower end portions (14a, 16a) remain guided in the respective second throughholes (21a, 21c) in the lower movable claw portions (10b, 10d) when said vertical bolts (13a, 13b, 15a, 15b) are pulled upwards out of said first throughholes (17a, 17b; 18a, 18b; 19a, 19b; 20a, 20b).