An electric motor includes: a stator having a sleeve shape; a rotor inside the stator; a shaft coupled to the rotor and stretching along a central axis of the stator; a board case on one end side of the stator in a direction along the central axis; a circuit board on an opposite side of the stator with the board case interposed; a heat generating component on a mounting surface, which is opposite to a surface of the circuit board oriented to a side of the stator; a casing that covers a side of the mounting surface; and a heat transfer component between a surface of the casing that faces the circuit board and the heat generating component. The board case is provided with an extension portion that extends toward the circuit board. The heat transfer component is formed with a first engagement portion with which the extension portion engages.