COMPONENT FOR FLOW RATE CONTROL DEVICE, AND FUEL INJECTION VALVE

An object of the present invention is to provide a fluid control device with an improved effect of suppressing blowhole generation. Therefore, a component for a flow rate control device of the present invention includes: a first component (A); a second component (B) fixed to the first component by a press-fitting portion ; a butt-welded portion connecting the first component and the second component; and a first gap and a second gap formed between mutually opposing surfaces of the first component and the second component. The first gap is provided on a side of the press-fitting portion with respect to the second gap between the press-fitting portion and the butt-welded portion, and is formed in a direction intersecting a press-fitting direction. The second gap is provided on a side of the butt-welded portion with respect to the first gap between the press-fitting portion and the welded portion, and is formed in a direction intersecting the first gap.