Improved sighting system for a fire arm, characterised in that it comprises a single indicator light (6); a sighting device (7) providing an alignment opening (8) with a longitudinal reference plane (XoX′) which is parallel or mainly parallel to the axis (Y-Y′) of the barrel (4) and which is aligned with the indicator light (6); an inclinometer to measure the elevation angle (A) of the fire arm (1); a ballistic calculator (9) connected to the indicator light (6) and to the inclinometer, making it possible to calculate the desired angle of inclination of the fire arm (1) as a function of the distance of the target (18) and to control the indicator light (6) so as to signal at what moment the measured elevation angle (A) corresponds to the calculated elevation angle.