A synchronous control system comprising one position detecting means and a plurality of drive control commanding units, wherein a first drive control commanding unit outputs a synchronous timing signal and a movement starting signal to a second drive control commanding unit, outputs a request signal to said position detecting means, and executes a synchronous operation in synchronism with position data from said position detecting means, and said second drive control commanding unit synchronizes an operation clock signal with said first drive control commanding unit based on the synchronous timing signal received from said first drive control commanding unit, and executes a synchronous operation in synchronism with the received movement starting signal, and the position data from said position detecting means.