Disclosed are a drive unit and an electric power steering device including the drive unit. The drive unit includes a rotating electric machine, a frame member, and a controller. The rotating electric machine has a stator that has a winding wound on the stator, a rotor disposed relative to the stator, and a shaft rotating together with the rotor. The frame member is disposed on one axial end of the rotating electric machine. The controller includes a substrate attached on one surface of the frame member facing away from the rotating electric machine, a heat generation element disposed on a heat generation element mounting surface of the substrate, the heat generation element mounting surface facing the frame member, and an electronic component disposed on an electronic component mounting surface of the substrate.