Disclosed is a control device wherein a control unit 1 is coaxially mounted with a motor 2. At the boundary between the motor 2 and the control unit 1, an upper frame 40 is disposed. In the control unit 1, a semiconductor module 35, an intermediate member 50, and a control substrate 3 are laminated. For the purpose of assembling the semiconductor module 35 and the intermediate member 50 to each other, a locking section 35f is provided to one of the semiconductor module 35 and the intermediate member 50, the other one of the semiconductor module and the intermediate member is provided with a section which the locking section 35f is to be locked to, and the semiconductor module 35 and the intermediate member 50 are aligned with each other.