An electric power steering device, comprising: a motor that has a stator including two independent coil windings with respect to a single rotor and causes a vehicle steering mechanism to rotate; and a control unit integrally attached to the motor; wherein the control unit has - a power supply circuit (13a, 13b) that generates a fixed voltage, - an input circuit (12a, 12b) that inputs operation information from various circuits, - an output circuit for driving a coil winding of the motor, - a power supply relay circuit (5a, 5b) that cuts off a current supply to the output circuit, - a central processing unit (10a, 10b) that calculates a control amount based on information from the input circuit (12a, 12b) and outputs a control signal to the output circuit, and - two sets of connectors (55a, 55b) for inputting or outputting, each set formed in one of two systems, respectively, so as to independently supply or cut off current to each coil winding of the motor, the central processing unit (10a, 10b) has an abnormality detection function of detecting an abnormality of the various circuits or coil winding, carries out communication with another central processing unit (10a, 10b), and is configured so that when an abnormality is detected in one system, control is continued by the control unit of the other system, wherein the control unit is disposed inside a single housing, and parts of the two systems, those being at least the power supply circuit (13a, 13b), input circuit (12a, 12b), and central processing unit (10a, 10b), are mounted in parallel on the same substrate; wherein one group of components including the power supply circuit (13a, 13b), the input circuit (12a, 12b), the output circuit, the power supply relay circuit (5a, 5b), the central processing unit (10a, 10b), and the connector (55a, 55b) is provided independently in each of the two systems, respectively, and the respective groups are disposed in parallel, where the connectors are extended with the same aspect through an outer peripheral inner side of the housing to the control unit, while maintaining the independence of each portion, and wherein the power supply circuit (13a, 13b), input circuit (12a, 12b), and central processing unit (10a, 10b) are independently disposed separated from the connectors (55a, 55b). a motor that has a stator including two independent coil windings with respect to a single rotor and causes a vehicle steering mechanism to rotate; and a control unit integrally attached to the motor; wherein the control unit has - a power supply circuit (13a, 13b) that generates a fixed voltage, - an input circuit (12a, 12b) that inputs operation information from various circuits, - an output circuit for driving a coil winding of the motor, - a power supply relay circuit (5a, 5b) that cuts off a current supply to the output circuit, - a central processing unit (10a, 10b) that calculates a control amount based on information from the input circuit (12a, 12b) and outputs a control signal to the output circuit, and - two sets of connectors (55a, 55b) for inputting or outputting, each set formed in one of two systems, respectively, - a power supply circuit (13a, 13b) that generates a fixed voltage, - an input circuit (12a, 12b) that inputs operation information from various circuits, - an output circuit for driving a coil winding of the motor, - a power supply relay circuit (5a, 5b) that cuts off a current supply to the output circuit, - a central processing unit (10a, 10b) that calculates a control amount based on information from the input circuit (12a, 12b) and outputs a control signal to the output circuit, and - two sets of connectors (55a, 55b) for inputting or outputting, each set formed in one of two systems, respectively, so as to independently supply or cut off current to each coil winding of the motor, the central processing unit (10a, 10b) has an abnormality detection function of detecting an abnormality of the various circuits or coil winding, carries out communication with another central processing unit (10a, 10b), and is configured so that when an abnormality is detected in one system, control is continued by the control unit of the other system, wherein the control unit is disposed inside a single housing, and parts of the two systems, those being at least the power supply circuit (13a, 13b), input circuit (12a, 12b), and central processing unit (10a, 10b), are mounted in parallel on the same substrate; wherein one group of components including the power supply circuit (13a, 13b), the input circuit (12a, 12b), the output circuit, the power supply relay circuit (5a, 5b), the central processing unit (10a, 10b), and the connector (55a, 55b) is provided independently in each of the two systems, respectively, and the respective groups are disposed in parallel, where the connectors are extended with the same aspect through an outer peripheral inner side of the housing to the control unit, while maintaining the independence of each portion, and wherein the power supply circuit (13a, 13b), input circuit (12a, 12b), and central processing unit (10a, 10b) are independently disposed separated from the connectors (55a, 55b).