Abstract: A method of and apparatus for measuring the amplitude of oscillation of the balance of a timepiece movement having an escapement adapted for disengagement and engagement, successively, the balance having a predetermined angle of lift. The time intervals between successive disengagement and engagement are measured, as are the durations of vibration of the balance. The number of pulses of a first frequency which are produced during at least one of the measured time intervals is counted. The number of pulses of a second frequency produced during at least one of the vibration durations also is counted. The first and second frequencies have a predetermined relationship with respect to each other. The number of counted pulses of the second frequency is divided by the number of counted pulses of the first frequency to thereby attain a quotient which is equal to the amplitude of oscillation.