A machine tool consists in a pair of slide ways set apart one from another and extending parallel with a longitudinal axis, a machining station between the slide ways, presenting a first zone and a second zone adjacent one to the other, and a traveling gantry set in motion along the slide ways and carrying a machining head positionable in the first and second zones. Installed alongside at least one of the slide ways and containing a supply of tools attachable to the machining head is a magazine equipped with a first changer element positioned to coincide with the first zone of the station, and a second changer element positioned to coincide with the second zone, so that whichever of the two zones the machining head happens to occupy at any given moment, the tool currently in use can be replaced with a tool from the magazine by the relative changer element with minimal loss of time.