A motor drive device driven by a three-phase AC, which drives a motor by an AC/DC converter and DC/AC converter controlled by a controller, and which has an electromagnetic contractor without an auxiliary contact in an input power circuit, which motor control device is provided at the controller with an off circuit of the electromagnetic contactor and a partial controller of the three-phase bridge circuit at the AC/DC converter, turns on an upper arm of a predetermined phase of the three-phase bridge circuit and turns on the lower arms of other phases in the state where the electromagnetic contactor is turned off, judges the presence of current in this state by the current detector, and, when the current detector detects current, uses a contact fusion detector to detecte contact fusion in the electromagnetic contactor and thereby can detect fusion of a contact in the electromagnetic contactor without an additional circuit.