In order to improve the isochronisms of the mechanical movement of a watch, the regulating members comprise at least two tourbillions mounted on a common rotating support driven by one or several barrel springs, such that the tourbillions make an orbital movement around the axis of rotation of the support. The tourbillions are connected by respective going trains to a differential gear, one of whose elements is immobilised by friction.

The invention concerns a watch with a mechanical movement of the type comprising at least two regulating systems (SR1, SR2) each including a mechanical oscillator and an escapement. The movement includes as many sub-assemblies (SE1, SE2) as there are regulating systems, each of said sub-assemblies including a regulating system (SR1, SR2), a barrel (B1, B2) and a going train transmitting energy from the barrel to the regulating system inside the sub-assembly. A differential display gear (Da) connects the barrel or the going train of each sub-assembly to the display (A) to average out the rate of the two sub-assemblies. In a preferred embodiment, the two sub-assemblies are mounted on a common rotating support (5) and their regulating systems are tourbillons which make an orbital movement about the center of the watch dial.