PURPOSE: To efficently absorb impulsive force with an apron side member by setting strength of the apron side member against a buckling load almost uniform.

CONSTITUTION: A member lower arm 16 is extended so as to lay it across a curved part 8, the end part is combined with an apron side member 7 on the front side, and the weakest curved part 8 against a buckling load F is reinforced with the member lower arm 16. Hereby, the locally weak part of an apron side member 4 is eliminated, and the strength is nearly uniformalized. In addition, the end part of a cross member 15 is fixed on the combined part side of the member lower arm 16 and the apron side member 7 on the front side, and the moving loads of an engine 13 and a transmission 14 are received with the cross member 15. Hereby, impulsive force in the early stage is absorbed with the apron side member 7 on the front side, next the member lower arm 16 is deformed by buckling so as to deform the whole apron side member 4 by buckling, and hence the impulsive force can be lightened.