An electric motor control device comprising: a first substrate having a surface provided with an electronic component (35, 36); a second substrate having a surface provided with a plurality of electronic components including a tall component (41 to 48) taller than the electronic component (35, 36) provided on the surface of the first substrate, the surface of the second substrate facing the surface of the first substrate; and a heat sink disposed between the surface of the first substrate and the surface of the second substrate, wherein the heat sink includes a component receiving portion and a heat dissipation portion, the component receiving portion being configured to receive the tall component (41 to 48) on the second substrate, the heat dissipation portion being configured to perform heat exchange between the first substrate and the second substrate and dissipate the heat generated by the first substrate and the heat generated by the second substrate through the heat sink to the air, and the component receiving portion and the heat dissipation portion being provided so as not to overlap with each other as viewed in a facing direction in which the first substrate and the second substrate face each other, characterized in that the component receiving portion is provided in a central portion of the heat sink, and the heat dissipation portion is provided in a peripheral portion around the component receiving portion in the heat sink, the first substrate is configured to control supply of electric power to an electrical motor and the second substrate is configured to supply the electric power to the electrical motor through control performed by the first substrate; the second substrate is located closer to the electrical motor than the first substrate is; a terminal block (40a, 40b) to which a terminal (61, 62) of the electrical motor is connected is provided on the surface of the second substrate, the surface of the second substrate being provided with the tall component, and the heat sink includes a terminal block receiving portion (73a, 73b) configured to receive the terminal block (40a, 40b), the terminal block receiving portion being provided so as not to overlap with the component receiving portion or the heat dissipation portion as viewed in the facing direction in which the first substrate and the second substrate face each other. a first substrate having a surface provided with an electronic component (35, 36); a second substrate having a surface provided with a plurality of electronic components including a tall component (41 to 48) taller than the electronic component (35, 36) provided on the surface of the first substrate, the surface of the second substrate facing the surface of the first substrate; and a heat sink disposed between the surface of the first substrate and the surface of the second substrate, wherein the heat sink includes a component receiving portion and a heat dissipation portion, the component receiving portion being configured to receive the tall component (41 to 48) on the second substrate, the heat dissipation portion being configured to perform heat exchange between the first substrate and the second substrate and dissipate the heat generated by the first substrate and the heat generated by the second substrate through the heat sink to the air, and the component receiving portion and the heat dissipation portion being provided so as not to overlap with each other as viewed in a facing direction in which the first substrate and the second substrate face each other, characterized in that the component receiving portion is provided in a central portion of the heat sink, and the heat dissipation portion is provided in a peripheral portion around the component receiving portion in the heat sink, the first substrate is configured to control supply of electric power to an electrical motor and the second substrate is configured to supply the electric power to the electrical motor through control performed by the first substrate; the second substrate is located closer to the electrical motor than the first substrate is; a terminal block (40a, 40b) to which a terminal (61, 62) of the electrical motor is connected is provided on the surface of the second substrate, the surface of the second substrate being provided with the tall component, and the heat sink includes a terminal block receiving portion (73a, 73b) configured to receive the terminal block (40a, 40b), the terminal block receiving portion being provided so as not to overlap with the component receiving portion or the heat dissipation portion as viewed in the facing direction in which the first substrate and the second substrate face each other.