A motor apparatus comprising: a motor having a rotation shaft for driving a load; a motor control device which is configured to control the motor; a motor housing which includes a plurality of motor housing cooling fins (101a, b), extending in a rotation shaft direction of the motor, on an outer periphery thereof and the motor housing is configured to accommodate the motor; a motor control device housing which is provided on an anti-load side of the motor housing and is configured to accommodate the motor control device; a plurality of motor control device housing cooling fins (115a, 115b), extending in the rotation shaft direction of the motor, on an outer periphery of the motor control device housing; motor housing cooling fins (101a, b) being arranged at equal distances from each other continuously around an entire circumference of the motor housing, wherein intervals in peripheral direction of the motor housing cooling fins (101a, b) and motor control device housing cooling fins (115a, b) are equal and passages for cooling air of the motor housing cooling fins (101a, b) and the motor control device housing cooling fins (115a, b) are aligned; motor control device cooling fins (112, 116) which are provided on the anti-load side of the motor control device housing, wherein the motor apparatus can be oriented such that the motor control device cooling fins (112, 116) on the anti-load side of the motor housing are provided in both vertical and horizontal directions; a cooling fan which is provided on the anti-load side of the motor control device cooling fins (112, 116); and an air duct cover which is configured to guide cooling air from the cooling fan, which is blown to the motor control device cooling fins, to the motor housing cooling fins (101a, b), wherein the air duct cover covers the motor control device housing cooling fins (115a, b), and wherein the air duct cover is not further extending to cover the motor housing cooling fins (101a, b), but is arranged up to end portions on the anti-load side of the motor housing cooling fins (101a, b), such that a covering length of the air duct cover is set up to the end portions of the motor housing cooling fins (101a, b) on the anti-load side of the motor. a motor having a rotation shaft for driving a load; a motor control device which is configured to control the motor; a motor housing which includes a plurality of motor housing cooling fins (101a, b), extending in a rotation shaft direction of the motor, on an outer periphery thereof and the motor housing is configured to accommodate the motor; a motor control device housing which is provided on an anti-load side of the motor housing and is configured to accommodate the motor control device; a plurality of motor control device housing cooling fins (115a, 115b), extending in the rotation shaft direction of the motor, on an outer periphery of the motor control device housing; motor housing cooling fins (101a, b) being arranged at equal distances from each other continuously around an entire circumference of the motor housing, wherein intervals in peripheral direction of the motor housing cooling fins (101a, b) and motor control device housing cooling fins (115a, b) are equal and passages for cooling air of the motor housing cooling fins (101a, b) and the motor control device housing cooling fins (115a, b) are aligned; motor control device cooling fins (112, 116) which are provided on the anti-load side of the motor control device housing, wherein the motor apparatus can be oriented such that the motor control device cooling fins (112, 116) on the anti-load side of the motor housing are provided in both vertical and horizontal directions; a cooling fan which is provided on the anti-load side of the motor control device cooling fins (112, 116); and an air duct cover which is configured to guide cooling air from the cooling fan, which is blown to the motor control device cooling fins, to the motor housing cooling fins (101a, b), wherein the air duct cover covers the motor control device housing cooling fins (115a, b), and wherein the air duct cover is not further extending to cover the motor housing cooling fins (101a, b), but is arranged up to end portions on the anti-load side of the motor housing cooling fins (101a, b), such that a covering length of the air duct cover is set up to the end portions of the motor housing cooling fins (101a, b) on the anti-load side of the motor.