PURPOSE: To improve supporting rigidity a pillar of a car body having an outrigger.

CONSTITUTION: An outrigger 7 extended in a car width direction to be orthogonal to a side member is arranged in a lower surf ace of a floor panel 1, and a receiving recessed part 17 is molded in a location orthogonal to a side member of the outrigger 7. The receiving recessed part 17 has side edges 18, 19 opposed to each other and a bottom edge 20, to connect the side edges 18, 19 and the bottom edge 20 to a bottom wall 3 and both side walls 4 of the side member. A vertical flange 21 provided in an end part of the outrigger 7 is in a lower end part of a B pillar 23 and connected to front/rear vertical surfaces of a B pillar inner 24, to connect a horizontal flange 22 to a lower surface 31 of the B pillar inner 24. Further, one end of a cross member 32 is connected to an end part aside to the car body center of the outrigger 7.