An automobile undercarriage component is provided with a web and a rib. The rib is configured so as to comprise a first section that is a section having the widest width and a second section that has a narrower width than the first section, and the second section having a narrower rib width than the first section as a result of an inner wall surface of the second section that is continuously formed from the web being provided so as to be adjacent to a facing outer surface wall.