A vehicle underfloor structure includes a battery having at least one connector projecting from a front end of the battery, and a protector covering and protecting the at least one connector from below, the protector having a rear portion attached to the battery and a front portion fastened to an attachment bar by a fastening bolt. The protector includes a fastening hole through which the fastening bolt is inserted, and a cutout connected to a rear portion of the fastening hole and allowing the fastening bolt to separate from the protector.