The watch, as exemplified by FIG. 6, comprises a motor 9 which drives the hands of a timepiece mechanism and a motor 15 which advances those of a chronographic mechanism. When the timepiece mechanism is in operation, a counter 98 receives every six seconds a pulse which opens a gate 85 which passes a pulse of 32 Hz and causes the shaft of the motor 9 to advance one step. When the stopwatch mechanism is in operation, a counter 78 receives ten pulses per second; every ten pulses it sends a pulse to the motor 15 and drives the chronographic second hand. When the chronographic mechanism is stopped, this second hand shows the seconds of chronometric time, the supplementary tenths of seconds being stored in the counter 78. The state of this counter 78 is compared with the state of an UP-DOWN counter 86 which determines the position of the second hand of the timepiece mechanism. The motor 9 then receives a number of pulses of 32 Hz equal to the numerical difference between the state of the counter 78 and that of the UP-DOWN counter 86. These pulses cause the tenths of a second over and above the last second of the chronometrically measured time, to be indicated by the second hand of the timepiece mechanism.