To securely enable a belt line reinforcement to pierce a pillar member at the time of collision of a vehicle.

A door main body 17 is disposed on a front pillar (pillar member) 6 in such a way that at least part of a front vertical wall 16a of the door main body 17 is overlapped with a rear vertical wall 8a of the front pillar 6 as seen in the longitudinal direction of the vehicle, a hinge reinforcement 21 having a hinge mounting seat 21c is disposed in the door main body 17 roughly along the front vertical wall 16a, and the belt line reinforcement 20 disposed along a belt line L is disposed to face the rear vertical wall 8a in this belt line part structure for an automobile. At a part of the rear vertical wall 8a of the front pillar 6 facing the belt line reinforcement 20, a swollen part 8d is formed to protrude toward the door main body 17 over the other parts of the rear vertical wall 8a, and recesses 21e and 21f are formed in the hinge reinforcement 21 around the belt line reinforcement.