A mechanical timepiece comprising a main spring, a front train wheel, and an escapement/advancement and speed governor device, the escapement/advancement and speed governor device including a timed annular balance, an escape wheel, and a pallet fork, further comprising a quartz oscillator forming a source vibration, an IC including a dividing part for inputting output signals output by the oscillation of the quartz oscillator, dividing the signals, and outputting signals related to a time, a storage member for operating the IC, and further a timing rate detecting part for detecting the timing rate of the mechanical timepiece, and a timed annular balance power generating control part formed so that it controls the frequency of the rotating oscillation of the timed annular balance and generate power by the rotating oscillation of the timed annular balance based on the divided signals divided by the dividing part and the operating state signals indicating the timing rate detected by the timing rate detecting part, whereby the rotation of the timed annular balance can be controlled accurately and the timing rate of the mechanical timepiece can be adjusted accurately. |