A component-mounting device according to an embodiment of the present invention includes a component-mounting board, a connector component, a heat sink, and a first screw portion. The component-mounting board includes a first surface and a second surface opposite to the first surface. The connector component includes a plurality of terminal-fixing portions that fixes a terminal extending in one axis direction orthogonal to the first surface and a base portion that connects between the plurality of terminal-fixing portions and includes an opening portion, the connector component being provided on the first surface. The heat sink faces the second surface and includes a first screw seat that faces the base portion in the one axis direction with the component-mounting board interposed between the first screw seat and the base portion. The first screw portion is disposed inside the opening portion and is engaged with the first screw seat through the component-mounting board.