To provide a driving device whose physical size can be reduced.

A heat sink 50 is provided in the axial direction of a motor case 10. This heat sink 50 is provided with a power module 60. The power module 60 is provided on the heat sink 50, and switches over the conduction to a coil. A control substrate 40 in which a control current for controlling a motor 2 flows is arranged in the heat sink 50, and is electrically connected with the power module 60. A power substrate 70 in which a driving current for driving the motor 2 flows is electrically connected with the power module 60, and arranged on the opposite side of the control substrate 40 relative to the heat sink 50. A control connector 49 is electrically connected with the control substrate 40, and the control current is inputted and outputted therethrough. A power connector 79 is electrically connected with the power substrate 70, and the driving current is inputted and outputted therethrough. The control connector 49 and the power connector 79 are arranged between the control substrate 40 and the power substrate 70.