A servomotor control system that includes a numerical control unit and servo control unit enables the use of learning control based on an angle synchronization method in high-speed oscillating motion performed by, for example, a jig grinder. The numerical control unit calculates a reference angle θ(=ωt), and also calculates a cyclic oscillation command F(t) according to the reference angle θ and a machining condition (angular velocity ω). The servo control unit calculates a difference between the value in the oscillation command F(t) and the position of the servomotor (positional difference ε) at intervals of a predetermined cycle, and performs learning control according to the reference angle θ, oscillation command F(t), and positional difference ε.