Protective Structure For Battery Pack

A protective structure for a battery pack mounted under a floor of a vehicle, includes: a case body accommodating the battery pack; and a under member arranged below the case body. The under member includes: a plurality of panels; and a plurality of fitting portions that connect adjacent panels of the plurality of panels to each other. Each of the plurality of fitting portions includes: a fitting recess provided to either one of the adjacent panels; and a fitting piece provided to the other of the adjacent panels and fitting into the fitting recess.