Provided is a coupling structure between a front pillar and a side sill of an automobile, which improves the steering stability of the automobile and realizes a high productivity. A reinforcing member 8 is provided inside a front pillar 1 having a closed cross-section so as to extend in the front-rear direction of the automobile. The reinforcing member 8 is coupled to a front pillar outer 2. An end portion of the reinforcing member 8 at the rear side of the automobile is extended toward a side sill 4 to form a reinforcing member extension 8a. The reinforcing member extension 8a is coupled to a side sill outer 5.