A component attaching structure for attaching a first component and a second component to each other. The first component has an attachment hole and an internal thread formed therein. The second component has an external thread formed thereon. The second component supports a sealing member, which seals an interface between an outer circumferential surface of the second component and an inner circumferential surface of the attaching hole at a position closer to a tip end of the second component than the external thread. If the direction in which the second component moves relative to the first component when the second component is attached to the first component is defined as an attaching direction, a distance between the external thread and the sealing member in the attaching direction is greater than the length of the internal thread in the attaching direction.