An electronic control unit comprising: two or more electronic components that each generate heat when energized; connection wires that connect the two or more electronic components ; and a heat sink for radiating heat of the two or more electronic components and the connection wires , wherein the two or more electronic components and the connection wires are mounted on a first substrate surface that is one of the sides of a substrate , wherein the heat sink is disposed spaced apart from a top surface, of each of the two or more electronic components and the connection wires , that is the surface opposite to the first substrate surface , wherein an intermediate member having an insulating property and a heat-conductive property is provided in a gap between the heat sink , and the two or more electronic components and connection wire abutting portions each of which is at least part of the connection wires in such a way as to abut against the heat sink , and the connection wire abutting portions or the two or more electronic components , wherein the top surface of a maximum heat generating component , which is an electronic component that generates heat most among the two or more electronic components when energized, is a plane; a portion, of the heat sink , that faces the top surface of the maximum heat generating component is part of a basic plane , which is a plane of the heat sink , characterized in that the connection wires are provided with flat-plate-shaped portions which connect the two or more electronic components , and in that in the connection wire abutting portion , there is provided a flat-plate-shaped heat-transfer protruding portion that is made of a material of a kind the same as the kind of the connection wire or a material having a heat-conductive property substantially the same as that of the connection wire and protrudes toward the heat sink from the flat-plate-shaped portions; the heat-transfer protruding portion abuts against the intermediate member . two or more electronic components that each generate heat when energized; connection wires that connect the two or more electronic components ; and a heat sink for radiating heat of the two or more electronic components and the connection wires , wherein the two or more electronic components and the connection wires are mounted on a first substrate surface that is one of the sides of a substrate , wherein the heat sink is disposed spaced apart from a top surface, of each of the two or more electronic components and the connection wires , that is the surface opposite to the first substrate surface , wherein an intermediate member having an insulating property and a heat-conductive property is provided in a gap between the heat sink , and the two or more electronic components and connection wire abutting portions each of which is at least part of the connection wires in such a way as to abut against the heat sink , and the connection wire abutting portions or the two or more electronic components , wherein the top surface of a maximum heat generating component , which is an electronic component that generates heat most among the two or more electronic components when energized, is a plane; a portion, of the heat sink , that faces the top surface of the maximum heat generating component is part of a basic plane , which is a plane of the heat sink , characterized in that the connection wires are provided with flat-plate-shaped portions which connect the two or more electronic components , and in that in the connection wire abutting portion , there is provided a flat-plate-shaped heat-transfer protruding portion that is made of a material of a kind the same as the kind of the connection wire or a material having a heat-conductive property substantially the same as that of the connection wire and protrudes toward the heat sink from the flat-plate-shaped portions; the heat-transfer protruding portion abuts against the intermediate member . <EOS>