A surgical handpiece for endocanalicular laser dacryocystorhinostomy, comprising - a handpiece body with an actuating knob, said actuating knob being designed to trigger a controlled step-by-step movement of a optical fibre, fed from a laser light source, only in the direction towards the operation site, said controlled movement being accomplished by means of a toothed slider in which the optical fibre is fixed, whereby with each trigger action the optical fibre is moved out of a cannula inserted in the handpiece body, disposed at the end of the handpiece and designed to lead the optical fibre to the operation site, for only one step of precisely determined length, the toothed slider allowing for movement of the optical fibre in one direction for more than one equally sized step; - the toothed slider, which is mounted in the handpiece body along the longitudinal axis of the body and has a row of serrated teeth disposed on its upper side, having a hollow interior in which the optical fibre is fed along the longitudinal axis of the slider, the optical fibre being fixed to the slider at the entry into the slider; the surgical handpiece additionally comprising - a shifting mechanism designed to execute a stepwise advancement of the optical fibre, fed through the handpiece, for a precisely determined step length towards the operation site, wherein said advancement is initiatable through a single manipulation of the actuating knob each time the end of the optical fibre section, which projects out of the cannula and with which the surgical operation is performed, burns out due to high energy of the outgoing laser light, - said shifting mechanism including a wedge-like member and a spring tongue with a spring, said wedge-like member and spring tongue being incorporated in the actuating knob wherein their task is to push the actuating knob in the direction towards the operation site; - said shifting mechanism further including the row of serrated teeth, said serrated teeth being disposed on the upper side of the slider, wherein their task is to ensure stepwise shifting of the toothed slider; - said shifting mechanism further including a return spring with a piston, said return spring being compressed when the actuating knob is pushed towards the cannula and expands once the pushing action on the actuating knob ceases, wherein the stretched spring pushes by means of the piston the actuating knob along with the spring tongue and the wedge-like member in backward direction, so that they all resume their original positions; - said shifting mechanism further including a locking ring with a pushing spring, said locking ring blocking the movement of the toothed slider when the actuating knob is in a resting state. - a handpiece body with an actuating knob, said actuating knob being designed to trigger a controlled step-by-step movement of a optical fibre, fed from a laser light source, only in the direction towards the operation site, said controlled movement being accomplished by means of a toothed slider in which the optical fibre is fixed, whereby with each trigger action the optical fibre is moved out of a cannula inserted in the handpiece body, disposed at the end of the handpiece and designed to lead the optical fibre to the operation site, for only one step of precisely determined length, the toothed slider allowing for movement of the optical fibre in one direction for more than one equally sized step; - the toothed slider, which is mounted in the handpiece body along the longitudinal axis of the body and has a row of serrated teeth disposed on its upper side, having a hollow interior in which the optical fibre is fed along the longitudinal axis of the slider, the optical fibre being fixed to the slider at the entry into the slider; the surgical handpiece additionally comprising - a shifting mechanism designed to execute a stepwise advancement of the optical fibre, fed through the handpiece, for a precisely determined step length towards the operation site, wherein said advancement is initiatable through a single manipulation of the actuating knob each time the end of the optical fibre section, which projects out of the cannula and with which the surgical operation is performed, burns out due to high energy of the outgoing laser light, - said shifting mechanism including a wedge-like member and a spring tongue with a spring, said wedge-like member and spring tongue being incorporated in the actuating knob wherein their task is to push the actuating knob in the direction towards the operation site; - said shifting mechanism further including the row of serrated teeth, said serrated teeth being disposed on the upper side of the slider, wherein their task is to ensure stepwise shifting of the toothed slider; - said shifting mechanism further including a return spring with a piston, said return spring being compressed when the actuating knob is pushed towards the cannula and expands once the pushing action on the actuating knob ceases, wherein the stretched spring pushes by means of the piston the actuating knob along with the spring tongue and the wedge-like member in backward direction, so that they all resume their original positions; - said shifting mechanism further including a locking ring with a pushing spring, said locking ring blocking the movement of the toothed slider when the actuating knob is in a resting state.