The present invention provides a power-supply management device which can efficiently connect and disconnect power supply to an electric-powered section, and a machine tool including the power-supply management device. The power-supply management device (101) detects a synchronization command of a control program, and compares an operation time of the electric-powered section between synchronizations in each control system which is a synchronization target by the synchronization command on the basis of the detected synchronization command. Then, the power-supply management device (101) disconnects the power supply to the electric-powered section belonging to the control system except the control system having the maximum operation time of the electric-powered section between the synchronizations, and restarts the power supply at the end of the synchronization in each control system.