The present invention concerns a simulator arranged for the simulation of firing, which simulator is intended to be mounted on a weapon with aiming means. The simulator contains an emitter for a simulation bean and an emitting device for an alignment beam, which device contains a reticle arranged in a first focal plane of an optical system. The optical system is characterized in that it contains means for beam-splitting, where the optical system has a second focal plane, and where the emitter for the simulation beam is arranged in an optical path or extension thereof containing the second focal plane.