PURPOSE: To enhance an energy absorbing characteristic at the time of collision by setting the fiber orientation angle to a specified angle at the end portion side of a car body and making the fiber orientation angle gradually approach 0° as it goes inboard in a side member structure formed by fiber reinforced resin.

CONSTITUTION: A front side member 4 as a side member disposed on the side portion of a car body of the front portion of the car body is formed in such a manner that fiber reinforced resin is formed into a shape having a square section by resin transfer molding forming, for example, and the front half portion 4a has a larger sectional area. In this case, the fiber orientation angle of the front side member 4 is set to 40°-60° at the front half portion 4a and it is orientated in such a manner as to gradually approach 0° as it goes from a changing portion 4b to the rear half portion 4c. Thus, at the time of collision of a vehicle, the car body end portion side of the side member 4 is compressed and deformed with good efficiency so as to satisfactorily absorb impact energy, and on the other hand, at the time of collision of the vehicle, the deformation is lessened at a portion of the side member 4 a little to the center of the car body to increase the reaction force.