A motor control system which makes a tool motor and a workpiece motor rotate in synchronization in a machine tool equipped with a tool motor, a workpiece motor, and a tool shaft movement motor which drives a linear shaft to change an intershaft distance between the tool shaft and the workpiece shaft, wherein when the power outage detector detects a power outage of the power supply during synchronous rotation of the tool motor and the workpiece motor, the operation of the forced deceleration circuit for causing forced deceleration of either one of the tool motor and workpiece motor is made to be delayed by a predetermined time and during that time the tool shaft movement motor is used to drive the linear shaft and separate the tool and workpiece as a retraction operation to thereby prevent damage to the tool and the workpiece at the time of a power outage.