An electric power steering device, comprising: a motor, which includes a stator including at least two independent coil winding groups, and is configured to rotate a steering mechanism of a vehicle; a drive control circuit (3a, 3b, 5a and 5b), which is configured to drive the at least two independent coil winding groups of the motor independently of each other; and a controller, which is configured to calculate a control amount through feedback control to output the control amount, to thereby cause the drive control circuit (3a, 3b, 5a and 5b) to drive the at least two independent coil winding groups, wherein: the at least two independent coil winding groups are controlled independently or in cooperation; the controller includes a failure detector, which is configured to detect a failure of the motor or the drive control circuit (3a, 3b, 5a and 5b); and the controller is configured to: output, when occurrence of a failure in one group out of the at least two independent coil winding groups is detected by the failure detector, a control amount so that control is continued solely by another normal group; characterized in that the controller is configured to: resume, when recovery of the one group from the failure is detected by the failure detector during a period in which the control is continued solely by the another group, cooperative control by the one group and the another group; and set, when starting the cooperative control, target current values of the one group and the another group to values different from a final target current value common to the at least two independent coil winding groups so that a sum of an actual current of the one group, which has recovered from the failure, and an actual current of the another group falls within an acceptable change amount based on an actual current value or a target current value of the another group at a time of the recovery from the failure, to thereby output respective control amounts for the cooperative control. a motor, which includes a stator including at least two independent coil winding groups, and is configured to rotate a steering mechanism of a vehicle; a drive control circuit (3a, 3b, 5a and 5b), which is configured to drive the at least two independent coil winding groups of the motor independently of each other; and a controller, which is configured to calculate a control amount through feedback control to output the control amount, to thereby cause the drive control circuit (3a, 3b, 5a and 5b) to drive the at least two independent coil winding groups, wherein: the at least two independent coil winding groups are controlled independently or in cooperation; the controller includes a failure detector, which is configured to detect a failure of the motor or the drive control circuit (3a, 3b, 5a and 5b); and the controller is configured to: output, when occurrence of a failure in one group out of the at least two independent coil winding groups is detected by the failure detector, a control amount so that control is continued solely by another normal group; the at least two independent coil winding groups are controlled independently or in cooperation; the controller includes a failure detector, which is configured to detect a failure of the motor or the drive control circuit (3a, 3b, 5a and 5b); and the controller is configured to: output, when occurrence of a failure in one group out of the at least two independent coil winding groups is detected by the failure detector, a control amount so that control is continued solely by another normal group; characterized in that the controller is configured to: resume, when recovery of the one group from the failure is detected by the failure detector during a period in which the control is continued solely by the another group, cooperative control by the one group and the another group; and set, when starting the cooperative control, target current values of the one group and the another group to values different from a final target current value common to the at least two independent coil winding groups so that a sum of an actual current of the one group, which has recovered from the failure, and an actual current of the another group falls within an acceptable change amount based on an actual current value or a target current value of the another group at a time of the recovery from the failure, to thereby output respective control amounts for the cooperative control. resume, when recovery of the one group from the failure is detected by the failure detector during a period in which the control is continued solely by the another group, cooperative control by the one group and the another group; and set, when starting the cooperative control, target current values of the one group and the another group to values different from a final target current value common to the at least two independent coil winding groups so that a sum of an actual current of the one group, which has recovered from the failure, and an actual current of the another group falls within an acceptable change amount based on an actual current value or a target current value of the another group at a time of the recovery from the failure, to thereby output respective control amounts for the cooperative control.