A marine chronometer includes a clock mounted on a support, for example mounted so that it can be inclined with respect to the support using a gimbal mounting, the clock including, inside a case, a mechanical clock movement driven by a barrel, and the clock also including a rewinding control member engaged with a rewinding geartrain for rewinding the barrel. The rewinding control member includes a rewinding control geartrain positioned on the outside of the clock, secured to a spindle passing through a wall of the case via a bearing, the through-spindle being engaged with the rewinding geartrain.