The invention relates to a timepiece comprising a mechanical movement and an adjusting device for adjusting the
travel time difference, the adjusting device comprising a rotary movable part and an adjusting movable part capable of controlling the angular position of the rotary movable part. The adjustment device further comprises a lever provided with a connecting
gear train, the lever being rotatable by a user-actuated button between a disengaged position and a coupled position, in which the adjustment movable is kinematically connected to the movable on the correction device via the connecting
gear train, and in which the adjustment movable is kinematically connected to the movable on the correction device via the connecting
gear train. The correction device comprises a control spindle equipped with a crown to enable actuation of the movable part, or an adjustment movable part kinematically connected to a driving movable part of an indicator via a connecting gear
train, said driving movable part being drivable by the correction device when correcting the data displayed by the indicator, the
travel time difference of the timepiece can be adjusted by moving the lever to the coupled position by actuating the button, translating the crown to move the control spindle to a given axial correction position, and then rotating the crown.