Abstract: An emergency push-button comprises a housing and a support rigidly connected to a movable actuation knob and axially movable therewith. The support acts on a releasing mechanism, operated by rotation of the knob about an axis parallel to the movement direction of the movable slider. The button further includes an axially movable member provided with at least one retaining tooth, which, upon lowering of the movable knob, rotates about an axis parallel to the moving direction of the knob, compelling the retaining tooth to release at least one protrusion provided on the housing and, once the movable member has cleared through a tripping action, it also rotates in a tripping manner carrying the retaining tooth to the position under the protrusion, preventing the movable member from moving back to a raised position thereof. The release of the retaining tooth may be obtained just through a rotating movement of the knob in a reversed direction with respect to the retaining movement.