Protecting helmet of the type provided with at least one inner shell for shock absorption and at least one outer rigid shell that define a front opening for the face of a user, as well as a protective visor at least rotatable between a lowered position intercepting, at least partially, the front opening and a raised position disengaged from said front opening, and a raising/lowering mechanism to raise/lower the protective visor, the raising/lowering mechanism comprising • at least one base member integral with, or made in a single piece with, or coincident with, part of the outer shell, and arranged in a side position with respect to said front opening; • a lever body mounted on said outer shell or said base member so as to rotate around a first axis (A-A) and provided with a support swinging with respect to said first axis (A-A) between a proximal position and a distal position with respect to said front opening, said support further comprising hooking means (21a, 21b, 26, 27) to hook with a corresponding side area of the protective visor; • elastic return-means constrained to said outer shell or said base member, and acting on said lever body to push it towards its distal position; • one or more hooking teeth (7a, 7b) integral with said side area of the protective visor and shaped for the engagement with said hooking means (21a, 21b, 26, 27) of the lever body; • at least one guide cam and a respective follower projection engaged with said guide cam, said at least one guide cam being integral with said at least one base member, and said respective follower projection being constrained so that to integrally rotate with said first side area of the protective visor, or vice versa; characterized in that said support of the lever body comprises at least one multiple-seat profile and in that said raising/lowering mechanism further comprises an intermediate disc-shaped element coupled with said support of said lever body so that to rotate with respect to said support around a second axis (B-B), and also to swing with respect to said first axis (A-A) integrally with said support of the lever body, and further comprising constraining means (29a, 29b) for the removable constraint to at least one of said hooking teeth (7a; 7b) of said protective visor in order to transmit at least the circular motion of the protective visor, during the raising or lowering thereof, to said intermediate disc-shaped element, as well as engaging means (31, 32, 33), at least integrally rotatable with said intermediate disc-shaped element, for the movable snap fitting with said at least one multiple-seat profile. • at least one base member integral with, or made in a single piece with, or coincident with, part of the outer shell, and arranged in a side position with respect to said front opening; • a lever body mounted on said outer shell or said base member so as to rotate around a first axis (A-A) and provided with a support swinging with respect to said first axis (A-A) between a proximal position and a distal position with respect to said front opening, said support further comprising hooking means (21a, 21b, 26, 27) to hook with a corresponding side area of the protective visor; • elastic return-means constrained to said outer shell or said base member, and acting on said lever body to push it towards its distal position; • one or more hooking teeth (7a, 7b) integral with said side area of the protective visor and shaped for the engagement with said hooking means (21a, 21b, 26, 27) of the lever body; • at least one guide cam and a respective follower projection engaged with said guide cam, said at least one guide cam being integral with said at least one base member, and said respective follower projection being constrained so that to integrally rotate with said first side area of the protective visor, or vice versa;