A drive device includes a motor, a control unit, a first fastener, and a second fastener. The control unit is arranged on a side of the motor in an axis direction of the motor. The first fastener is arranged in a wall part of a cylindrical motor case of the motor opposing to the control unit, on an inner side of a peripheral wall of the motor case in a radial direction. The second fastener is tightened with the first fastener so as to connect the motor and the control unit with each other.