STRUCTURE FOR UNDERRUN PROTECTOR

[Object] To provide a structure of an underrun protection that efficiently achieves weight reduction. [Arrangement for Attaining the Object] A structure of an underrun protection 10 bound to a plurality of brackets disposed at the front or rear portion of a frame of a vehicle characterized in that: a hollow having a closed section is defined by a distal face of a longitudinal direction of the vehicle, a proximal face of the longitudinal direction, an upper face, and a lower face; and lightening holes 51, 52 and 53 are formed on at least one of the upper face and the lower face of the underrun protection 10.