A drive device includes a motor, having a stator on which a winding wire group is wound, a rotor disposed relative to the stator, and a shaft rotating in one body with the rotor are included, a controller disposed on one axial end of the motor and having a substrate on which electronic components for controlling a power supply to the winding wire group are implemented, a frame member facing the substrate and having a substrate supporter that supports the substrate in a contacting manner, a boss protruding from the frame member toward the substrate, and an engager fixedly disposed on the substrate and having elastically-deformable multiple claws that engagingly hold the boss in a binding manner. This arrangement reduces the volume of the drive device.