PURPOSE: To perform efficient energy absorption at the time of collision in such a way that a number of notched parts are juxtaposed in the longitudinal direction at the flange parts of the hat section member which is joined to the vehicular body panel.

CONSTITUTION: A hat section member 7 is joined to the lower part of a vehicular body panel 1. A number of vertically notched parts 2d are regularly juxtaposed on the upper and lower flange parts 2b, 2c of the hat section member 2. In consequence, when an impact force at the time of collision is applied through a bumper to a vehicular body frame 3, since thickness of the vehicular body panel 1 is adequately thinner than that of the hat section member 2, and some region with the notched parts 2d is weak in its strength, the hat section member 2 is transformed like bellows, and the collision energy can be effectively absorbed in this transformation.