A pair of left and right upper members are provided to extend substantially along a vehicle longitudinal direction on both sides of the left and right front side frames in a vehicle width direction and to have their rear ends joined to front pillars disposed at lateral ends of a cabin. Each of the upper members has a substantially rectangular shape in cross section constituted by left and right walls and upper and lower walls. A weak portion, such as a recess, is provided in at least one corner portion having no flange among corner portions formed between adjacent walls of the upper members.