The shielding portion 306 includes the main part 61 that faces the coated portion 42 and is separated from the coated portion 42, and a support portion 362. The main part 61 and the leg part 63 are separate members that are joined together, or have a configuration that is integrally formed by two-color molding. The main part 61 has a flat plate shape having an inner periphery portion 362a forming an opening. The shielding portion 306 is fixed to the circuit board 8 at a plurality of positions. The support portion 362 comes into contact with the lower surface of the coated portion 42 and supports the integral body of the coated portion 42 and the graphite sheet 4 from below. The inner periphery portion 362a is formed as a part of the support portion 362. The inner periphery portion 362a is formed so as to surround the outer periphery portion 51 of the heat conductive portion 5. The inner periphery portion 362a is located outside the outer periphery portion 51 of the heat conductive portion 5. Alternatively, the inner periphery portion 362a may be configured to be in contact with the outer periphery portion 51 of the heat conductive portion 5.

The shielding portion 306 of the fourth embodiment is provided at a position between a portion of the circuit board where no heat-generating component is mounted and the circuit-board-side surface of the coated portion 42. According to such configuration, even if the graphite sheet 4 in a portion reinforced by the coated portion 42 is chipped, the small pieces can be received by the shielding portion 306.