Provided are a motor control device (1) for controlling a motor (2) having a plurality of phases, for quickly and accurately detecting a phase in which an open-state fault has occurred when the open-state fault occurs in a target phase. When a power-supply voltage (Vb) is equal to or higher than a predetermined voltage (Vthr), a motor rotation speed (ω) is equal to or lower than a predetermined speed (ωthr), a target x-phase voltage command (Vx*) is not in the vicinity of zero, a current (Ix) of the target x-phase is equal to or lower than a predetermined current (Iu_thr), and a state in which a control error is equal to or larger than a predetermined error is detected over a predetermined time period or longer, occurrence of an open-state fault in the target phase is determined.