In an apparatus for measuring an angular velocity variation rate of a rotary axle, an approximately circular disc shaped plate is attached approximately concentrically around the rotary axle, in addition to a first pair of velocity pulse generators, each velocity pulse generator of the first pair being dispose around pulse circumference of the plate on a first virtual line passing through a center of the rotatory axle with one of the velocity pulse generators positioned in an 180.degree. revolution difference with respect to each other, each velocity pulse generator of a second pair being disposed around the circumference of the plate on a second virtual line passing through the center of the rotary axle and being inclined through an angle of 180.degree./m to the first virtual line set when a variation in the angular velocity variation rate indicate signal occurs m-th number of times per revolution of the rotatory axle.